slick.grid.js

/**
 * @license
 * (c) 2009-2010 Michael Leibman
 * michael{dot}leibman{at}gmail{dot}com
 * http://github.com/mleibman/slickgrid
 * Distributed under MIT license.
 * All rights reserved.
 *
 * SlickGrid v2.0 alpha
 *
 * NOTES:
 *     Cell/row DOM manipulations are done directly bypassing jQuery's DOM manipulation methods.
 *     This increases the speed dramatically, but can only be done safely because there are no event handlers
 *     or data associated with any cell/row DOM nodes.  Cell editors must make sure they implement .destroy()
 *     and do proper cleanup.
 */

// make sure required JavaScript modules are loaded
if (typeof jQuery === "undefined") {
    throw "SlickGrid requires jquery module to be loaded";
}
if (!jQuery.fn.drag) {
    throw "SlickGrid requires jquery.event.drag module to be loaded";
}
if (typeof Slick === "undefined") {
    throw "slick.core.js not loaded";
}


(function($) {
    // Slick.Grid
    $.extend(true, window, {
        Slick: {
            Grid: SlickGrid
        }
    });

    var scrollbarDimensions; // shared across all grids on this page

    //////////////////////////////////////////////////////////////////////////////////////////////
    // SlickGrid class implementation (available as Slick.Grid)

    /**
     * @constructor
     * @param {Node}              container   Container node to create the grid in.
     * @param {Array,Object}      data        An array of objects for databinding.
     * @param {Array}             columns     An array of column definitions.
     * @param {Object}            options     Grid options.
     **/
    function SlickGrid(container,data,columns,options) {
        /// <summary>
        /// Create and manage virtual grid in the specified $container,
        /// connecting it to the specified data source. Data is presented
        /// as a grid with the specified columns and data.length rows.
        /// Options alter behaviour of the grid.
        /// </summary>

        // settings
        var defaults = {
            headerHeight: 25,
            rowHeight: 25,
            defaultColumnWidth: 80,
            enableAddRow: false,
            leaveSpaceForNewRows: false,
            editable: false,
            autoEdit: true,
            enableCellNavigation: true,
            enableCellRangeSelection: false,
            enableColumnReorder: true,
            asyncEditorLoading: false,
            asyncEditorLoadDelay: 100,
            forceFitColumns: false,
            enableAsyncPostRender: false,
            asyncPostRenderDelay: 60,
            autoHeight: false,
            editorLock: Slick.GlobalEditorLock,
            showHeaderRow: false,
            headerRowHeight: 25,
            showTopPanel: false,
            topPanelHeight: 25,
            syncColumnCellResize: false,
            formatterFactory: null,
            editorFactory: null,
            cellFlashingCssClass: "flashing",
            selectedCellCssClass: "selected",
            multiSelect: true
        },
        gridData;

        var columnDefaults = {
            name: "",
            resizable: true,
            sortable: false,
            minWidth: 30,
            rerenderOnResize: false,
            unselectable: false,
            groupTotalsFormatter: null
        };

        // scroller
        var maxSupportedCssHeight;      // browser's breaking point
        var th;                         // virtual height
        var h;                          // real scrollable height
        var ph;                         // page height
        var n;                          // number of pages
        var cj;                         // "jumpiness" coefficient

        var page = 0;                   // current page
        var offset = 0;                 // current page offset
        var scrollDir = 1;

        // private
        var $container;
        var uid = "slickgrid_" + Math.round(1000000 * Math.random());
        var self = this;
        var $headerScroller;
        var $headers;
        var $headerRow, $headerRowScroller;
        var $topPanelScroller;
        var $topPanel;
        var $viewport;
        var $canvas;
        var $style;
        var stylesheet;
        var viewportH, viewportW;
        var viewportHasHScroll;
        var headerColumnWidthDiff, headerColumnHeightDiff, cellWidthDiff, cellHeightDiff;  // padding+border
        var absoluteColumnMinWidth;

        var activeRow, activeCell;
        var activeCellNode = null;
        var currentEditor = null;
        var serializedEditorValue;
        var editController;

        var rowsCache = {};
        var renderedRows = 0;
        var numVisibleRows;
        var prevScrollTop = 0;
        var scrollTop = 0;
        var lastRenderedScrollTop = 0;
        var prevScrollLeft = 0;
        var avgRowRenderTime = 10;

        var selectionModel;
        var selectedRows = [];

        var plugins = [];
        var cellCssClasses = {};

        var columnsById = {};
        var sortColumnId;
        var sortAsc = true;

        // async call handles
        var h_editorLoader = null;
        var h_render = null;
        var h_postrender = null;
        var postProcessedRows = {};
        var postProcessToRow = null;
        var postProcessFromRow = null;

        // perf counters
        var counter_rows_rendered = 0;
        var counter_rows_removed = 0;


        //////////////////////////////////////////////////////////////////////////////////////////////
        // Initialization

        function init() {
            /// <summary>
            /// Initialize 'this' (self) instance of a SlickGrid.
            /// This function is called by the constructor.
            /// </summary>

            $container = $(container);

            gridData = data;

            maxSupportedCssHeight = getMaxSupportedCssHeight();

            scrollbarDimensions = scrollbarDimensions || measureScrollbar(); // skip measurement if already have dimensions
            options = $.extend({},defaults,options);
            columnDefaults.width = options.defaultColumnWidth;

            // validate loaded JavaScript modules against requested options
            if (options.enableColumnReorder && !$.fn.sortable) {
                throw new Error("SlickGrid's \"enableColumnReorder = true\" option requires jquery-ui.sortable module to be loaded");
            }

            editController = {
                "commitCurrentEdit": commitCurrentEdit,
                "cancelCurrentEdit": cancelCurrentEdit
            };

            $container
                .empty()
                .attr("tabIndex",0)
                .attr("hideFocus",true)
                .css("overflow","hidden")
                .css("outline",0)
                .addClass(uid)
                .addClass("ui-widget");

            // set up a positioning container if needed
            if (!/relative|absolute|fixed/.test($container.css("position")))
                $container.css("position","relative");

            $headerScroller = $("<div class='slick-header ui-state-default' style='overflow:hidden;position:relative;' />").appendTo($container);
            $headers = $("<div class='slick-header-columns' style='width:100000px; left:-10000px' />").appendTo($headerScroller);

            $headerRowScroller = $("<div class='slick-headerrow ui-state-default' style='overflow:hidden;position:relative;' />").appendTo($container);
            $headerRow = $("<div class='slick-headerrow-columns' style='width:100000px;' />").appendTo($headerRowScroller);

            $topPanelScroller = $("<div class='slick-top-panel-scroller ui-state-default' style='overflow:hidden;position:relative;' />").appendTo($container);
            $topPanel = $("<div class='slick-top-panel' style='width:100000px' />").appendTo($topPanelScroller);

            if (!options.showTopPanel) {
                $topPanelScroller.hide();
            }

            if (!options.showHeaderRow) {
                $headerRowScroller.hide();
            }

            $viewport = $("<div class='slick-viewport' tabIndex='0' hideFocus style='width:100%;overflow-x:auto;outline:0;position:relative;overflow-y:auto;'>").appendTo($container);
            $canvas = $("<div class='grid-canvas' tabIndex='0' hideFocus />").appendTo($viewport);

            // header columns and cells may have different padding/border skewing width calculations (box-sizing, hello?)
            // calculate the diff so we can set consistent sizes
            measureCellPaddingAndBorder();

            // for usability reasons, all text selection in SlickGrid is disabled
            // with the exception of input and textarea elements (selection must
            // be enabled there so that editors work as expected); note that
            // selection in grid cells (grid body) is already unavailable in
            // all browsers except IE
            disableSelection($headers); // disable all text selection in header (including input and textarea)
            $viewport.bind("selectstart.ui", function (event) { return $(event.target).is("input,textarea"); }); // disable text selection in grid cells except in input and textarea elements (this is IE-specific, because selectstart event will only fire in IE)

            viewportW = parseFloat($.css($container[0], "width", true));

            createColumnHeaders();
            setupColumnSort();
            createCssRules();
            resizeAndRender();

            bindAncestorScrollEvents();
            $viewport.bind("scroll.slickgrid", handleScroll);
            $container.bind("resize.slickgrid", resizeAndRender);
            $headerScroller
                .bind("contextmenu.slickgrid", handleHeaderContextMenu)
                .bind("click.slickgrid", handleHeaderClick);

            $canvas
                .bind("keydown.slickgrid", handleKeyDown)
                .bind("click.slickgrid", handleClick)
                .bind("dblclick.slickgrid", handleDblClick)
                .bind("contextmenu.slickgrid", handleContextMenu)
                .bind("draginit", handleDragInit)
                .bind("dragstart", handleDragStart)
                .bind("drag", handleDrag)
                .bind("dragend", handleDragEnd);

            $canvas.delegate(".slick-cell", "mouseenter", handleMouseEnter);
            $canvas.delegate(".slick-cell", "mouseleave", handleMouseLeave);
        }

        function registerPlugin(plugin) {
            plugins.unshift(plugin);
            plugin.init(self);
        }

        function unregisterPlugin(plugin) {
            for (var i = plugins.length; i >= 0; i--) {
                if (plugins[i] === plugin) {
                    if (plugins[i].destroy) {
                        plugins[i].destroy();
                    }
                    plugins.splice(i, 1);
                    break;
                }
            }
        }

        function setSelectionModel(model) {
            if (selectionModel) {
                selectionModel.onSelectedRangesChanged.unsubscribe(handleSelectedRangesChanged);
                if (selectionModel.destroy) {
                    selectionModel.destroy();
                }
            }

            selectionModel = model;
            selectionModel.init(self);

            selectionModel.onSelectedRangesChanged.subscribe(handleSelectedRangesChanged);
        }

        function getSelectionModel() {
            return selectionModel;
        }

        function getCanvasNode() {
            return $canvas[0];
        }

        function measureScrollbar() {
            /// <summary>
            /// Measure width of a vertical scrollbar
            /// and height of a horizontal scrollbar.
            /// </summary
            /// <returns>
            /// { width: pixelWidth, height: pixelHeight }
            /// </returns>
            var $c = $("<div style='position:absolute; top:-10000px; left:-10000px; width:100px; height:100px; overflow:scroll;'></div>").appendTo("body");
            var dim = { width: $c.width() - $c[0].clientWidth, height: $c.height() - $c[0].clientHeight };
            $c.remove();
            return dim;
        }

        function getRowWidth() {
            var rowWidth = 0;
            var i = columns.length;
            while (i--) {
                rowWidth += (columns[i].currentWidth || columns[i].width || columnDefaults.width);
            }
            return rowWidth;
        }

        function setCanvasWidth(width) {
            $canvas.width(width);
            viewportHasHScroll = (width > viewportW - scrollbarDimensions.width);
        }

        function disableSelection($target) {
            /// <summary>
            /// Disable text selection (using mouse) in
            /// the specified target.
            /// </summary
            if ($target && $target.jquery) {
                $target.attr('unselectable', 'on').css('MozUserSelect', 'none').bind('selectstart.ui', function() { return false; }); // from jquery:ui.core.js 1.7.2
            }
        }

        function getMaxSupportedCssHeight() {
            var increment = 1000000;
            var supportedHeight = 0;
            // FF reports the height back but still renders blank after ~6M px
            var testUpTo = ($.browser.mozilla) ? 5000000 : 1000000000;
            var div = $("<div style='display:none' />").appendTo(document.body);

            while (supportedHeight <= testUpTo) {
                div.css("height", supportedHeight + increment);
                if (div.height() !== supportedHeight + increment)
                    break;
                else
                    supportedHeight += increment;
            }

            div.remove();
            return supportedHeight;
        }

        // TODO:  this is static.  need to handle page mutation.
        function bindAncestorScrollEvents() {
            var elem = $canvas[0];
            while ((elem = elem.parentNode) != document.body) {
                // bind to scroll containers only
                if (elem == $viewport[0] || elem.scrollWidth != elem.clientWidth || elem.scrollHeight != elem.clientHeight)
                    $(elem).bind("scroll.slickgrid", handleActiveCellPositionChange);
            }
        }

        function unbindAncestorScrollEvents() {
            $canvas.parents().unbind("scroll.slickgrid");
        }

        function updateColumnHeader(columnId, title, toolTip) {
            var idx = getColumnIndex(columnId);
            var $header = $headers.children().eq(idx);
            if ($header) {
                columns[idx].name = title;
                columns[idx].toolTip = toolTip;
                $header
                    .attr("title", toolTip || title || "")
                    .children().eq(0).html(title);
            }
        }

        function getHeaderRow() {
            return $headerRow[0];
        }

        function getHeaderRowColumn(columnId) {
            var idx = getColumnIndex(columnId);
            var $header = $headerRow.children().eq(idx);
            return $header && $header[0];
        }


        function createColumnHeaders() {
            var i;

            function hoverBegin() {
                $(this).addClass("ui-state-hover");
            }
            function hoverEnd() {
                $(this).removeClass("ui-state-hover");
            }

            $headers.empty();
            $headerRow.empty();
            columnsById = {};

            for (i = 0; i < columns.length; i++) {
                var m = columns[i] = $.extend({},columnDefaults,columns[i]);
                columnsById[m.id] = i;

                var header = $("<div class='ui-state-default slick-header-column' id='" + uid + m.id + "' />")
                    .html("<span class='slick-column-name'>" + m.name + "</span>")
                    .width((m.currentWidth || m.width) - headerColumnWidthDiff)
                    .attr("title", m.toolTip || m.name || "")
                    .data("fieldId", m.id)
                    .appendTo($headers);

                if (options.enableColumnReorder || m.sortable) {
                    header.hover(hoverBegin, hoverEnd);
                }

                if (m.sortable) {
                    header.append("<span class='slick-sort-indicator' />");
                }

                if (options.showHeaderRow) {
                    $("<div class='ui-state-default slick-headerrow-column c" + i + "'></div>").appendTo($headerRow);
                }
            }

            setSortColumn(sortColumnId,sortAsc);
            setupColumnResize();
            if (options.enableColumnReorder) {
                setupColumnReorder();
            }
        }

        function setupColumnSort() {
            $headers.click(function(e) {
                if ($(e.target).hasClass("slick-resizable-handle")) {
                    return;
                }

                var $col = $(e.target).closest(".slick-header-column");
                if (!$col.length)
                    return;

                var column = columns[getSiblingIndex($col[0])];
                if (column.sortable) {
                    if (!getEditorLock().commitCurrentEdit())
                        return;

                    if (column.id === sortColumnId) {
                        sortAsc = !sortAsc;
                    }
                    else {
                        sortColumnId = column.id;
                        sortAsc = true;
                    }

                    setSortColumn(sortColumnId,sortAsc);
                    trigger(self.onSort, {sortCol:column,sortAsc:sortAsc});
                }
            });
        }

        function setupColumnReorder() {
            $headers.sortable({
                containment: "parent",
                axis: "x",
                cursor: "default",
                tolerance: "intersection",
                helper: "clone",
                placeholder: "slick-sortable-placeholder ui-state-default slick-header-column",
                forcePlaceholderSize: true,
                start: function(e, ui) { $(ui.helper).addClass("slick-header-column-active"); },
                beforeStop: function(e, ui) { $(ui.helper).removeClass("slick-header-column-active"); },
                stop: function(e) {
                    if (!getEditorLock().commitCurrentEdit()) {
                        $(this).sortable("cancel");
                        return;
                    }

                    var reorderedIds = $headers.sortable("toArray");
                    var reorderedColumns = [];
                    for (var i=0; i<reorderedIds.length; i++) {
                        reorderedColumns.push(columns[getColumnIndex(reorderedIds[i].replace(uid,""))]);
                    }
                    setColumns(reorderedColumns);

                    trigger(self.onColumnsReordered, {});
                    e.stopPropagation();
                    setupColumnResize();
                }
            });
        }

        function setupColumnResize() {
            var $col, j, c, pageX, columnElements, minPageX, maxPageX, firstResizable, lastResizable, originalCanvasWidth;
            columnElements = $headers.children();
            columnElements.find(".slick-resizable-handle").remove();
            columnElements.each(function(i,e) {
                if (columns[i].resizable) {
                    if (firstResizable === undefined) { firstResizable = i; }
                    lastResizable = i;
                }
            });
            columnElements.each(function(i,e) {
                if ((firstResizable !== undefined && i < firstResizable) || (options.forceFitColumns && i >= lastResizable)) { return; }
                $col = $(e);
                $("<div class='slick-resizable-handle' />")
                    .appendTo(e)
                    .bind("dragstart", function(e,dd) {
                        if (!getEditorLock().commitCurrentEdit()) { return false; }
                        pageX = e.pageX;
                        $(this).parent().addClass("slick-header-column-active");
                        var shrinkLeewayOnRight = null, stretchLeewayOnRight = null;
                        // lock each column's width option to current width
                        columnElements.each(function(i,e) { columns[i].previousWidth = $(e).outerWidth(); });
                        if (options.forceFitColumns) {
                            shrinkLeewayOnRight = 0;
                            stretchLeewayOnRight = 0;
                            // colums on right affect maxPageX/minPageX
                            for (j = i + 1; j < columnElements.length; j++) {
                                c = columns[j];
                                if (c.resizable) {
                                    if (stretchLeewayOnRight !== null) {
                                        if (c.maxWidth) {
                                            stretchLeewayOnRight += c.maxWidth - c.previousWidth;
                                        }
                                        else {
                                            stretchLeewayOnRight = null;
                                        }
                                    }
                                    shrinkLeewayOnRight += c.previousWidth - Math.max(c.minWidth || 0, absoluteColumnMinWidth);
                                }
                            }
                        }
                        var shrinkLeewayOnLeft = 0, stretchLeewayOnLeft = 0;
                        for (j = 0; j <= i; j++) {
                            // columns on left only affect minPageX
                            c = columns[j];
                            if (c.resizable) {
                                if (stretchLeewayOnLeft !== null) {
                                    if (c.maxWidth) {
                                        stretchLeewayOnLeft += c.maxWidth - c.previousWidth;
                                    }
                                    else {
                                        stretchLeewayOnLeft = null;
                                    }
                                }
                                shrinkLeewayOnLeft += c.previousWidth - Math.max(c.minWidth || 0, absoluteColumnMinWidth);
                            }
                        }
                        if (shrinkLeewayOnRight === null) { shrinkLeewayOnRight = 100000; }
                        if (shrinkLeewayOnLeft === null) { shrinkLeewayOnLeft = 100000; }
                        if (stretchLeewayOnRight === null) { stretchLeewayOnRight = 100000; }
                        if (stretchLeewayOnLeft === null) { stretchLeewayOnLeft = 100000; }
                        maxPageX = pageX + Math.min(shrinkLeewayOnRight, stretchLeewayOnLeft);
                        minPageX = pageX - Math.min(shrinkLeewayOnLeft, stretchLeewayOnRight);
                        originalCanvasWidth = $canvas.width();
                    })
                    .bind("drag", function(e,dd) {
                        var actualMinWidth, d = Math.min(maxPageX, Math.max(minPageX, e.pageX)) - pageX, x, ci;
                        if (d < 0) { // shrink column
                            x = d;
                            for (j = i; j >= 0; j--) {
                                c = columns[j];
                                if (c.resizable) {
                                    actualMinWidth = Math.max(c.minWidth || 0, absoluteColumnMinWidth);
                                    if (x && c.previousWidth + x < actualMinWidth) {
                                        x += c.previousWidth - actualMinWidth;
                                        styleColumnWidth(j, actualMinWidth, options.syncColumnCellResize);
                                    } else {
                                        styleColumnWidth(j, c.previousWidth + x, options.syncColumnCellResize);
                                        x = 0;
                                    }
                                }
                            }

                            if (options.forceFitColumns) {
                                x = -d;
                                for (j = i + 1; j < columnElements.length; j++) {
                                    c = columns[j];
                                    if (c.resizable) {
                                        if (x && c.maxWidth && (c.maxWidth - c.previousWidth < x)) {
                                            x -= c.maxWidth - c.previousWidth;
                                            styleColumnWidth(j, c.maxWidth, options.syncColumnCellResize);
                                        } else {
                                            styleColumnWidth(j, c.previousWidth + x, options.syncColumnCellResize);
                                            x = 0;
                                        }
                                    }
                                }
                            } else if (options.syncColumnCellResize) {
                                setCanvasWidth(originalCanvasWidth + d);
                            }
                        } else { // stretch column
                            x = d;
                            for (j = i; j >= 0; j--) {
                                c = columns[j];
                                if (c.resizable) {
                                    if (x && c.maxWidth && (c.maxWidth - c.previousWidth < x)) {
                                        x -= c.maxWidth - c.previousWidth;
                                        styleColumnWidth(j, c.maxWidth, options.syncColumnCellResize);
                                    } else {
                                        styleColumnWidth(j, c.previousWidth + x, options.syncColumnCellResize);
                                        x = 0;
                                    }
                                }
                            }

                            if (options.forceFitColumns) {
                                x = -d;
                                for (j = i + 1; j < columnElements.length; j++) {
                                    c = columns[j];
                                    if (c.resizable) {
                                        actualMinWidth = Math.max(c.minWidth || 0, absoluteColumnMinWidth);
                                        if (x && c.previousWidth + x < actualMinWidth) {
                                            x += c.previousWidth - actualMinWidth;
                                            styleColumnWidth(j, actualMinWidth, options.syncColumnCellResize);
                                        } else {
                                            styleColumnWidth(j, c.previousWidth + x, options.syncColumnCellResize);
                                            x = 0;
                                        }
                                    }
                                }
                            } else if (options.syncColumnCellResize) {
                                setCanvasWidth(originalCanvasWidth + d);
                            }
                        }
                    })
                    .bind("dragend", function(e,dd) {
                        var newWidth;
                        $(this).parent().removeClass("slick-header-column-active");
                        for (j = 0; j < columnElements.length; j++) {
                            c = columns[j];
                            newWidth = $(columnElements[j]).outerWidth();

                            if (c.previousWidth !== newWidth && c.rerenderOnResize) {
                                invalidateAllRows();
                            }
                            if (options.forceFitColumns) {
                                c.width = Math.floor(c.width * (newWidth - c.previousWidth) / c.previousWidth) + c.width;
                            } else {
                                c.width = newWidth;
                            }
                            if (!options.syncColumnCellResize && c.previousWidth !== newWidth) {
                                styleColumnWidth(j, newWidth, true);
                            }
                        }
                        resizeCanvas();
                        trigger(self.onColumnsResized, {});
                    });
                });
        }

        function getVBoxDelta($el) {
            var p = ["borderTopWidth", "borderBottomWidth", "paddingTop", "paddingBottom"];
            var delta = 0;
            $.each(p, function(n,val) { delta += parseFloat($el.css(val)) || 0; });
            return delta;
        }

        function measureCellPaddingAndBorder() {
            var el;
            var h = ["borderLeftWidth", "borderRightWidth", "paddingLeft", "paddingRight"];
            var v = ["borderTopWidth", "borderBottomWidth", "paddingTop", "paddingBottom"];

            el = $("<div class='ui-state-default slick-header-column' style='visibility:hidden'>-</div>").appendTo($headers);
            headerColumnWidthDiff = headerColumnHeightDiff = 0;
            $.each(h, function(n,val) { headerColumnWidthDiff += parseFloat(el.css(val)) || 0; });
            $.each(v, function(n,val) { headerColumnHeightDiff += parseFloat(el.css(val)) || 0; });
            el.remove();

            var r = $("<div class='slick-row' />").appendTo($canvas);
            el = $("<div class='slick-cell' id='' style='visibility:hidden'>-</div>").appendTo(r);
            cellWidthDiff = cellHeightDiff = 0;
            $.each(h, function(n,val) { cellWidthDiff += parseFloat(el.css(val)) || 0; });
            $.each(v, function(n,val) { cellHeightDiff += parseFloat(el.css(val)) || 0; });
            r.remove();

            absoluteColumnMinWidth = Math.max(headerColumnWidthDiff,cellWidthDiff);
        }

        function createCssRules() {
            $style = $("<style type='text/css' rel='stylesheet' />").appendTo($("head"));
            var rowHeight = (options.rowHeight - cellHeightDiff);

            var rules = [
                "." + uid + " .slick-header-column { left: 10000px; }",
                "." + uid + " .slick-top-panel { height:" + options.topPanelHeight + "px; }",
                "." + uid + " .slick-headerrow-columns { height:" + options.headerRowHeight + "px; }",
                "." + uid + " .slick-cell { height:" + rowHeight + "px; }",
                "." + uid + " .slick-row { width:" + getRowWidth() + "px; }"
            ];

            for (var i=0; i<columns.length; i++) {
                rules.push(
                    "." + uid + " .c" + i + " { " +
                    "width:" + ((columns[i].currentWidth || columns[i].width) - cellWidthDiff) + "px; " +
                    " } ");
            }

            if ($style[0].styleSheet) { // IE
                $style[0].styleSheet.cssText = rules.join("");
            }
            else {
                $style[0].appendChild(document.createTextNode(rules.join(" ")));
            }

            var sheets = document.styleSheets;
            for (var i=0; i<sheets.length; i++) {
                if ((sheets[i].ownerNode || sheets[i].owningElement) == $style[0]) {
                    stylesheet = sheets[i];
                    break;
                }
            }
        }

        function findCssRule(selector) {
            var rules = (stylesheet.cssRules || stylesheet.rules);

            for (var i=0; i<rules.length; i++) {
                if (rules[i].selectorText == selector)
                    return rules[i];
            }

            return null;
        }

        function findCssRuleForCell(index) {
            return findCssRule("." + uid + " .c" + index);
        }

        function removeCssRules() {
            $style.remove();
        }

        function destroy() {
            getEditorLock().cancelCurrentEdit();

            trigger(self.onBeforeDestroy, {});

            for (var i = 0; i < plugins.length; i++) {
                unregisterPlugin(plugin);
            }

            if (options.enableColumnReorder && $headers.sortable)
                $headers.sortable("destroy");

            unbindAncestorScrollEvents();
            $container.unbind(".slickgrid");
            removeCssRules();

            $canvas.unbind("draginit dragstart dragend drag");
            $container.empty().removeClass(uid);
        }


        //////////////////////////////////////////////////////////////////////////////////////////////
        // General

        function trigger(evt, args, e) {
            e = e || new Slick.EventData();
            args = args || args;
            args.grid = self;
            return evt.notify(args, e, self);
        }

        function getEditorLock() {
            return options.editorLock;
        }

        function getEditController() {
            return editController;
        }

        function getColumnIndex(id) {
            return columnsById[id];
        }

        function autosizeColumns() {
            var i, c,
                widths = [],
                shrinkLeeway = 0,
                availWidth = (options.autoHeight ? viewportW : viewportW - scrollbarDimensions.width), // with AutoHeight, we do not need to accomodate the vertical scroll bar
                total = 0,
                existingTotal = 0;

            for (i = 0; i < columns.length; i++) {
                c = columns[i];
                widths.push(c.width);
                existingTotal += c.width;
                shrinkLeeway += c.width - Math.max(c.minWidth || 0, absoluteColumnMinWidth);
            }

            total = existingTotal;

            invalidateAllRows();

            // shrink
            while (total > availWidth) {
                if (!shrinkLeeway) { return; }
                var shrinkProportion = (total - availWidth) / shrinkLeeway;
                for (i = 0; i < columns.length && total > availWidth; i++) {
                    c = columns[i];
                    if (!c.resizable || c.minWidth === c.width || c.width === absoluteColumnMinWidth) { continue; }
                    var shrinkSize = Math.floor(shrinkProportion * (c.width - Math.max(c.minWidth || 0, absoluteColumnMinWidth))) || 1;
                    total -= shrinkSize;
                    widths[i] -= shrinkSize;
                }
            }

            // grow
            var previousTotal = total;
            while (total < availWidth) {
                var growProportion = availWidth / total;
                for (i = 0; i < columns.length && total < availWidth; i++) {
                    c = columns[i];
                    if (!c.resizable || c.maxWidth <= c.width) { continue; }
                    var growSize = Math.min(Math.floor(growProportion * c.width) - c.width, (c.maxWidth - c.width) || 1000000) || 1;
                    total += growSize;
                    widths[i] += growSize;
                }
                if (previousTotal == total) break; // if total is not changing, will result in infinite loop
                previousTotal = total;
            }

            for (i=0; i<columns.length; i++) {
                styleColumnWidth(i, columns[i].currentWidth = widths[i], true);
            }

            resizeCanvas();
        }

        function styleColumnWidth(index,width,styleCells) {
            columns[index].currentWidth = width;
            $headers.children().eq(index).css("width", width - headerColumnWidthDiff);
            if (styleCells) {
                findCssRuleForCell(index).style.width = (width - cellWidthDiff) + "px";
                findCssRule("." + uid + " .slick-row").style.width = getRowWidth() + "px";
            }
        }

        function setSortColumn(columnId, ascending) {
            sortColumnId = columnId;
            sortAsc = ascending;
            var columnIndex = getColumnIndex(sortColumnId);

            $headers.children().removeClass("slick-header-column-sorted");
            $headers.find(".slick-sort-indicator").removeClass("slick-sort-indicator-asc slick-sort-indicator-desc");

            if (columnIndex != null) {
                $headers.children().eq(columnIndex)
                    .addClass("slick-header-column-sorted")
                    .find(".slick-sort-indicator")
                        .addClass(sortAsc ? "slick-sort-indicator-asc" : "slick-sort-indicator-desc");
            }
        }

        function handleSelectedRangesChanged(e, ranges) {
            selectedRows = [];
            var hash = {};
            for (var i = 0; i < ranges.length; i++) {
                for (var j = ranges[i].fromRow; j <= ranges[i].toRow; j++) {
                    if (!hash[j]) {  // prevent duplicates
                        selectedRows.push(j);
                    }
                    hash[j] = {};
                    for (var k = ranges[i].fromCell; k <= ranges[i].toCell; k++) {
                        hash[j][columns[k].id] = options.selectedCellCssClass;
                    }
                }
            }

            setCellCssStyles(options.selectedCellCssClass, hash);

            trigger(self.onSelectedRowsChanged, {rows:getSelectedRows()}, e);
        }

        function getColumns() {
            return columns;
        }

        function setColumns(columnDefinitions) {
            columns = columnDefinitions;
            invalidateAllRows();
            createColumnHeaders();
            removeCssRules();
            createCssRules();
            resizeAndRender();
            handleScroll();
        }

        function getOptions() {
            return options;
        }

        function setOptions(args) {
            if (!getEditorLock().commitCurrentEdit()) {
                return;
            }

            makeActiveCellNormal();

            if (options.enableAddRow !== args.enableAddRow) {
                invalidateRow(getDataLength());
            }

            options = $.extend(options,args);

            render();
        }

        function setData(newData,scrollToTop) {
            invalidateAllRows();
            gridData = newData;
            if (scrollToTop)
                scrollTo(0);
        }

        function getData() {
            return gridData;
        }

        function getDataLength() {
            if (gridData.getLength) {
                return gridData.getLength();
            }
            else {
                return gridData.length;
            }
        }

        function getDataItem(i) {
            if (gridData.getItem) {
                return gridData.getItem(i);
            }
            else {
                return gridData[i];
            }
        }

        function getTopPanel() {
            return $topPanel[0];
        }

        function showTopPanel() {
            options.showTopPanel = true;
            $topPanelScroller.slideDown("fast", resizeCanvas);
        }

        function hideTopPanel() {
            options.showTopPanel = false;
            $topPanelScroller.slideUp("fast", resizeCanvas);
        }

        function showHeaderRowColumns() {
            options.showHeaderRow = true;
            $headerRowScroller.slideDown("fast", resizeCanvas);
        }

        function hideHeaderRowColumns() {
            options.showHeaderRow = false;
            $headerRowScroller.slideUp("fast", resizeCanvas);
        }

        //////////////////////////////////////////////////////////////////////////////////////////////
        // Rendering / Scrolling

        function scrollTo(y) {
            var oldOffset = offset;

            page = Math.min(n-1, Math.floor(y / ph));
            offset = Math.round(page * cj);
            var newScrollTop = y - offset;

            if (offset != oldOffset) {
                var range = getVisibleRange(newScrollTop);
                cleanupRows(range.top,range.bottom);
                updateRowPositions();
            }

            if (prevScrollTop != newScrollTop) {
                scrollDir = (prevScrollTop + oldOffset < newScrollTop + offset) ? 1 : -1;
                $viewport[0].scrollTop = (lastRenderedScrollTop = scrollTop = prevScrollTop = newScrollTop);

                trigger(self.onViewportChanged, {});
            }
        }

        function defaultFormatter(row, cell, value, columnDef, dataContext) {
            return (value === null || value === undefined) ? "" : value;
        }

        function getFormatter(column) {
            return column.formatter ||
                    (options.formatterFactory && options.formatterFactory.getFormatter(column)) ||
                    defaultFormatter;
        }

        function getEditor(column) {
            return column.editor || (options.editorFactory && options.editorFactory.getEditor(column));
        }

        function appendRowHtml(stringArray,row) {
            var d = getDataItem(row);
            var dataLoading = row < getDataLength() && !d;
            var cellCss;
            var css = "slick-row " +
                (dataLoading ? " loading" : "") +
                (row % 2 == 1 ? ' odd' : ' even');

            // if the user has specified a function to provide additional per-row css classes, call it here
            if (options.rowCssClasses) {
                css += " " + options.rowCssClasses(d);
            }

            if (d instanceof Slick.GroupTotals) {
                css += " slick-group-totals";
            }

            stringArray.push("<div class='ui-widget-content " + css + "' row='" + row + "' style='top:" + (options.rowHeight*row-offset) + "px'>");

            if (d instanceof Slick.Group) {
                stringArray.push("<div class='slick-cell slick-group" + (row === activeRow ? " active" : "") + "'>");
                stringArray.push("<span class='slick-group-toggle " + (d.collapsed ? "collapsed" : "expanded") + "'></span>");
                stringArray.push(d.title);
                stringArray.push("</div>");
            }
            else {
                for (var i=0, cols=columns.length; i<cols; i++) {
                    var m = columns[i];

                    cellCss = "slick-cell c" + i + (m.cssClass ? " " + m.cssClass : "");
                    if (row === activeRow && i === activeCell) {
                        cellCss += (" active");
                    }

                    if (!(d instanceof Slick.NonDataRow)) {
                        // TODO:  merge them together in the setter
                        for (var key in cellCssClasses) {
                            if (cellCssClasses[key][row] && cellCssClasses[key][row][m.id]) {
                                cellCss += (" " + cellCssClasses[key][row][m.id]);
                            }
                        }
                    }

                    stringArray.push("<div class='" + cellCss + "'>");

                    // if there is a corresponding row (if not, this is the Add New row or this data hasn't been loaded yet)
                    if (d) {
                        if (d instanceof Slick.GroupTotals) {
                            if (m.groupTotalsFormatter) {
                                stringArray.push(m.groupTotalsFormatter(d, m));
                            }
                        }
                        else {
                            stringArray.push(getFormatter(m)(row, i, d[m.field], m, d));
                        }
                    }

                    stringArray.push("</div>");
                }
            }

            stringArray.push("</div>");
        }

        function cleanupRows(rangeToKeep) {
            for (var i in rowsCache) {
                if (((i = parseInt(i, 10)) !== activeRow) && (i < rangeToKeep.top || i > rangeToKeep.bottom)) {
                    removeRowFromCache(i);
                }
            }
        }

        function invalidate() {
           updateRowCount();
           invalidateAllRows();
           render();
        }

        function invalidateAllRows() {
            if (currentEditor) {
                makeActiveCellNormal();
            }
            for (var row in rowsCache) {
                removeRowFromCache(row);
            }
        }

        function removeRowFromCache(row) {
            var node = rowsCache[row];
            if (!node) { return; }
            $canvas[0].removeChild(node);

            delete rowsCache[row];
            delete postProcessedRows[row];
            renderedRows--;
            counter_rows_removed++;
        }

        function invalidateRows(rows) {
            var i, rl;
            if (!rows || !rows.length) { return; }
            scrollDir = 0;
            for (i=0, rl=rows.length; i<rl; i++) {
                if (currentEditor && activeRow === i) {
                    makeActiveCellNormal();
                }

                if (rowsCache[rows[i]]) {
                    removeRowFromCache(rows[i]);
                }
            }
        }

        function invalidateRow(row) {
            invalidateRows([row]);
        }

        function updateCell(row,cell) {
            var cellNode = getCellNode(row,cell);
            if (!cellNode) {
                return;
            }

            var m = columns[cell], d = getDataItem(row);
            if (currentEditor && activeRow === row && activeCell === cell) {
                currentEditor.loadValue(d);
            }
            else {
                cellNode.innerHTML = d ? getFormatter(m)(row, cell, d[m.field], m, d) : "";
                invalidatePostProcessingResults(row);
            }
        }

        function updateRow(row) {
            if (!rowsCache[row]) { return; }

            $(rowsCache[row]).children().each(function(i) {
                var m = columns[i];
                if (row === activeRow && i === activeCell && currentEditor) {
                    currentEditor.loadValue(getDataItem(activeRow));
                }
                else if (getDataItem(row)) {
                    this.innerHTML = getFormatter(m)(row, i, getDataItem(row)[m.field], m, getDataItem(row));
                }
                else {
                    this.innerHTML = "";
                }
            });

            invalidatePostProcessingResults(row);
        }

        function getViewportHeight() {
            return parseFloat($.css($container[0], "height", true)) -
                options.headerHeight -
                getVBoxDelta($headers) -
                (options.showTopPanel ? options.topPanelHeight + getVBoxDelta($topPanelScroller) : 0) -
                (options.showHeaderRow ? options.headerRowHeight + getVBoxDelta($headerRowScroller) : 0);
        }

        function resizeCanvas() {
            if (options.autoHeight) {
                viewportH = options.rowHeight * (getDataLength() + (options.enableAddRow ? 1 : 0) + (options.leaveSpaceForNewRows? numVisibleRows - 1 : 0));
            }
            else {
                viewportH = getViewportHeight();
            }

            numVisibleRows = Math.ceil(viewportH / options.rowHeight);
            viewportW = parseFloat($.css($container[0], "width", true));
            $viewport.height(viewportH);

            var w = 0, i = columns.length;
            while (i--) {
                w += columns[i].currentWidth || columns[i].width;
            }
            setCanvasWidth(w);

            updateRowCount();
            render();
        }

        function resizeAndRender() {
            if (options.forceFitColumns) {
                autosizeColumns();
            } else {
                resizeCanvas();
            }
        }

        function updateRowCount() {
            var newRowCount = getDataLength() + (options.enableAddRow?1:0) + (options.leaveSpaceForNewRows?numVisibleRows-1:0);
            var oldH = h;

            // remove the rows that are now outside of the data range
            // this helps avoid redundant calls to .removeRow() when the size of the data decreased by thousands of rows
            var l = options.enableAddRow ? getDataLength() : getDataLength() - 1;
            for (var i in rowsCache) {
                if (i >= l) {
                    removeRowFromCache(i);
                }
            }
            th = Math.max(options.rowHeight * newRowCount, viewportH - scrollbarDimensions.height);
            if (th < maxSupportedCssHeight) {
                // just one page
                h = ph = th;
                n = 1;
                cj = 0;
            }
            else {
                // break into pages
                h = maxSupportedCssHeight;
                ph = h / 100;
                n = Math.floor(th / ph);
                cj = (th - h) / (n - 1);
            }

            if (h !== oldH) {
                $canvas.css("height",h);
                scrollTop = $viewport[0].scrollTop;
            }

            var oldScrollTopInRange = (scrollTop + offset <= th - viewportH);

            if (th == 0 || scrollTop == 0) {
                page = offset = 0;
            }
            else if (oldScrollTopInRange) {
                // maintain virtual position
                scrollTo(scrollTop+offset);
            }
            else {
                // scroll to bottom
                scrollTo(th-viewportH);
            }

            if (h != oldH && options.autoHeight) {
                resizeCanvas();
            }
        }

        function getVisibleRange(viewportTop) {
            if (viewportTop == null)
                viewportTop = scrollTop;

            return {
                top: Math.floor((scrollTop+offset)/options.rowHeight),
                bottom: Math.ceil((scrollTop+offset+viewportH)/options.rowHeight)
            };
        }

        function getRenderedRange(viewportTop) {
            var range = getVisibleRange(viewportTop);
            var buffer = Math.round(viewportH/options.rowHeight);
            var minBuffer = 3;

            if (scrollDir == -1) {
                range.top -= buffer;
                range.bottom += minBuffer;
            }
            else if (scrollDir == 1) {
                range.top -= minBuffer;
                range.bottom += buffer;
            }
            else {
                range.top -= minBuffer;
                range.bottom += minBuffer;
            }

            range.top = Math.max(0,range.top);
            range.bottom = Math.min(options.enableAddRow ? getDataLength() : getDataLength() - 1,range.bottom);

            return range;
        }

        function renderRows(range) {
            var i, l,
                parentNode = $canvas[0],
                rowsBefore = renderedRows,
                stringArray = [],
                rows = [],
                startTimestamp = new Date(),
                needToReselectCell = false;

            for (i = range.top; i <= range.bottom; i++) {
                if (rowsCache[i]) { continue; }
                renderedRows++;
                rows.push(i);
                appendRowHtml(stringArray,i);
                if (activeCellNode && activeRow === i) {
                    needToReselectCell = true;
                }
                counter_rows_rendered++;
            }

            var x = document.createElement("div");
            x.innerHTML = stringArray.join("");

            for (i = 0, l = x.childNodes.length; i < l; i++) {
                rowsCache[rows[i]] = parentNode.appendChild(x.firstChild);
            }

            if (needToReselectCell) {
                activeCellNode = getCellNode(activeRow,activeCell);
            }

            if (renderedRows - rowsBefore > 5) {
                avgRowRenderTime = (new Date() - startTimestamp) / (renderedRows - rowsBefore);
            }
        }

        function startPostProcessing() {
            if (!options.enableAsyncPostRender) { return; }
            clearTimeout(h_postrender);
            h_postrender = setTimeout(asyncPostProcessRows, options.asyncPostRenderDelay);
        }

        function invalidatePostProcessingResults(row) {
            delete postProcessedRows[row];
            postProcessFromRow = Math.min(postProcessFromRow,row);
            postProcessToRow = Math.max(postProcessToRow,row);
            startPostProcessing();
        }

        function updateRowPositions() {
            for (var row in rowsCache) {
                rowsCache[row].style.top = (row*options.rowHeight-offset) + "px";
            }
        }

        function render() {
            var visible = getVisibleRange();
            var rendered = getRenderedRange();

            // remove rows no longer in the viewport
            cleanupRows(rendered);

            // add new rows
            renderRows(rendered);

            postProcessFromRow = visible.top;
            postProcessToRow = Math.min(options.enableAddRow ? getDataLength() : getDataLength() - 1, visible.bottom);
            startPostProcessing();

            lastRenderedScrollTop = scrollTop;
            h_render = null;
        }

        function handleScroll() {
            scrollTop = $viewport[0].scrollTop;
            var scrollLeft = $viewport[0].scrollLeft;
            var scrollDist = Math.abs(scrollTop - prevScrollTop);

            if (scrollLeft !== prevScrollLeft) {
                prevScrollLeft = scrollLeft;
                $headerScroller[0].scrollLeft = scrollLeft;
                $topPanelScroller[0].scrollLeft = scrollLeft;
                $headerRowScroller[0].scrollLeft = scrollLeft;
            }

            if (scrollDist) {
                scrollDir = prevScrollTop < scrollTop ? 1 : -1;
                prevScrollTop = scrollTop;

                // switch virtual pages if needed
                if (scrollDist < viewportH) {
                    scrollTo(scrollTop + offset);
                }
                else {
                    var oldOffset = offset;
                    page = Math.min(n - 1, Math.floor(scrollTop * ((th - viewportH) / (h - viewportH)) * (1 / ph)));
                    offset = Math.round(page * cj);
                    if (oldOffset != offset)
                        invalidateAllRows();
                }

                if (h_render)
                    clearTimeout(h_render);

                if (Math.abs(lastRenderedScrollTop - scrollTop) < viewportH)
                    render();
                else
                    h_render = setTimeout(render, 50);

                trigger(self.onViewportChanged, {});
            }

            trigger(self.onScroll, {scrollLeft:scrollLeft, scrollTop:scrollTop});
        }

        function asyncPostProcessRows() {
            while (postProcessFromRow <= postProcessToRow) {
                var row = (scrollDir >= 0) ? postProcessFromRow++ : postProcessToRow--;
                var rowNode = rowsCache[row];
                if (!rowNode || postProcessedRows[row] || row>=getDataLength()) { continue; }

                var d = getDataItem(row), cellNodes = rowNode.childNodes;
                for (var i=0, j=0, l=columns.length; i<l; ++i) {
                    var m = columns[i];
                    if (m.asyncPostRender) { m.asyncPostRender(cellNodes[j], postProcessFromRow, d, m); }
                    ++j;
                }

                postProcessedRows[row] = true;
                h_postrender = setTimeout(asyncPostProcessRows, options.asyncPostRenderDelay);
                return;
            }
        }

        function addCellCssStyles(key,hash) {
            if (cellCssClasses[key]) {
                throw "addCellCssStyles: cell CSS hash with key '" + key + "' already exists.";
            }

            cellCssClasses[key] = hash;

            for (var row in rowsCache) {
                if (hash[row]) {
                    if (!(getDataItem(row) instanceof Slick.NonDataRow)) {
                        for (var columnId in hash[row]) {
                            $(rowsCache[row]).children().eq(getColumnIndex(columnId))
                                .addClass(hash[row][columnId]);
                        }
                    }
                }
            }
        }

        function removeCellCssStyles(key) {
            if (!cellCssClasses[key]) {
                return;
            }

            for (var row in rowsCache) {
                if (cellCssClasses[key][row]) {
                    for (var columnId in cellCssClasses[key][row]) {
                        $(rowsCache[row]).children().eq(getColumnIndex(columnId))
                            .removeClass(cellCssClasses[key][row][columnId]);
                    }
                }
            }

            delete cellCssClasses[key];
        }

        function setCellCssStyles(key,hash) {
            removeCellCssStyles(key);
            addCellCssStyles(key,hash);
        }

        function flashCell(row, cell, speed) {
            speed = speed || 100;
            if (rowsCache[row]) {
                var $cell = $(getCellNode(row,cell));

                function toggleCellClass(times) {
                    if (!times) return;
                    setTimeout(function() {
                        $cell.queue(function() {
                            $cell.toggleClass(options.cellFlashingCssClass).dequeue();
                            toggleCellClass(times-1);
                        });
                    },
                    speed);
                }

                toggleCellClass(4);
            }
        }

        //////////////////////////////////////////////////////////////////////////////////////////////
        // Interactivity

        function getSiblingIndex(node) {
            var idx = 0;
            while (node && node.previousSibling) {
                idx++;
                node = node.previousSibling;
            }
            return idx;
        }

        function handleDragInit(e,dd) {
            var cell = getCellFromEvent(e);
            if (!cell || !cellExists(cell.row, cell.cell)) {
                return false;
            }

            retval = trigger(self.onDragInit, dd, e);
            if (e.isImmediatePropagationStopped()) {
                return retval;
            }
        }

        function handleDragStart(e,dd) {
            var cell = getCellFromEvent(e);
            if (!cell || !cellExists(cell.row, cell.cell)) {
                return false;
            }

            var retval = trigger(self.onDragStart, dd, e);
            if (e.isImmediatePropagationStopped()) {
                return retval;
            }

            return false;
        }

        function handleDrag(e,dd) {
            return trigger(self.onDrag, dd, e);
        }

        function handleDragEnd(e,dd) {
            trigger(self.onDragEnd, dd, e);
        }

        function handleKeyDown(e) {
            trigger(self.onKeyDown, {}, e);
            var handled = e.isImmediatePropagationStopped();

            if (!handled) {
                if (!e.shiftKey && !e.altKey && !e.ctrlKey) {
                    if (e.which == 27) {
                        if (!getEditorLock().isActive()) {
                            return; // no editing mode to cancel, allow bubbling and default processing (exit without cancelling the event)
                        }
                        cancelEditAndSetFocus();
                    }
                    else if (e.which == 37) {
                        navigateLeft();
                    }
                    else if (e.which == 39) {
                        navigateRight();
                    }
                    else if (e.which == 38) {
                        navigateUp();
                    }
                    else if (e.which == 40) {
                        navigateDown();
                    }
                    else if (e.which == 9) {
                        navigateNext();
                    }
                    else if (e.which == 13) {
                        if (options.editable) {
                            if (currentEditor) {
                                // adding new row
                                if (activeRow === getDataLength()) {
                                    navigateDown();
                                }
                                else {
                                    commitEditAndSetFocus();
                                }
                            } else {
                                if (getEditorLock().commitCurrentEdit()) {
                                    makeActiveCellEditable();
                                }
                            }
                        }
                    }
                    else
                        return;
                }
                else if (e.which == 9 && e.shiftKey && !e.ctrlKey && !e.altKey) {
                    navigatePrev();
                }
                else
                    return;
            }

            // the event has been handled so don't let parent element (bubbling/propagation) or browser (default) handle it
            e.stopPropagation();
            e.preventDefault();
            try {
                e.originalEvent.keyCode = 0; // prevent default behaviour for special keys in IE browsers (F3, F5, etc.)
            }
            catch (error) {} // ignore exceptions - setting the original event's keycode throws access denied exception for "Ctrl" (hitting control key only, nothing else), "Shift" (maybe others)
        }

        function handleClick(e) {
            var cell = getCellFromEvent(e);
            if (!cell || (currentEditor !== null && activeRow == cell.row && activeCell == cell.cell)) {
                return;
            }

            trigger(self.onClick, {row:cell.row, cell:cell.cell}, e);
            if (e.isImmediatePropagationStopped()) {
                return;
            }

            if (options.enableCellNavigation && !columns[cell.cell].unselectable) {
                if (!getEditorLock().isActive() || getEditorLock().commitCurrentEdit()) {
                    scrollRowIntoView(cell.row,false);
                    setActiveCellInternal(getCellNode(cell.row,cell.cell), (cell.row === getDataLength()) || options.autoEdit);
                }
            }
        }

        function handleContextMenu(e) {
            var $cell = $(e.target).closest(".slick-cell", $canvas);
            if ($cell.length === 0) { return; }

            // are we editing this cell?
            if (activeCellNode === $cell[0] && currentEditor !== null) { return; }

            trigger(self.onContextMenu, {}, e);
        }

        function handleDblClick(e) {
            var cell = getCellFromEvent(e);
            if (!cell || (currentEditor !== null && activeRow == cell.row && activeCell == cell.cell)) {
                return;
            }

            trigger(self.onDblClick, {row:cell.row, cell:cell.cell}, e);
            if (e.isImmediatePropagationStopped()) {
                return;
            }

            if (options.editable) {
                gotoCell(cell.row, cell.cell, true);
            }
        }

        function handleHeaderContextMenu(e) {
            var $header = $(e.target).closest(".slick-header-column", ".slick-header-columns");
            var column = $header && columns[self.getColumnIndex($header.data("fieldId"))];
            trigger(self.onHeaderContextMenu, {column: column}, e);
        }

        function handleHeaderClick(e) {
            var $header = $(e.target).closest(".slick-header-column", ".slick-header-columns");
            var column = $header && columns[self.getColumnIndex($header.data("fieldId"))];
            trigger(self.onHeaderClick, {column: column}, e);
        }

        function handleMouseEnter(e) {
            trigger(self.onMouseEnter, {}, e);
        }

        function handleMouseLeave(e) {
            trigger(self.onMouseLeave, {}, e);
        }

        function cellExists(row,cell) {
            return !(row < 0 || row >= getDataLength() || cell < 0 || cell >= columns.length);
        }

        function getCellFromPoint(x,y) {
            var row = Math.floor((y+offset)/options.rowHeight);
            var cell = 0;

            var w = 0;
            for (var i=0; i<columns.length && w<x; i++) {
                w += (columns[i].currentWidth || columns[i].width);
                cell++;
            }

            if (cell < 0) {
                cell = 0;
            }

            return {row:row,cell:cell-1};
        }

        function getCellFromEvent(e) {
            var $cell = $(e.target).closest(".slick-cell", $canvas);
            if (!$cell.length)
                return null;

            return {
                row: $cell.parent().attr("row") | 0,
                cell: getSiblingIndex($cell[0])
            };
        }

        function getCellNodeBox(row,cell) {
             if (!cellExists(row,cell))
                 return null;

             var y1 = row * options.rowHeight - offset;
             var y2 = y1 + options.rowHeight - 1;
             var x1 = 0;
             for (var i=0; i<cell; i++) {
                 x1 += (columns[i].currentWidth || columns[i].width);
             }
             var x2 = x1 + (columns[cell].currentWidth || columns[cell].width);

             return {
                 top: y1,
                 left: x1,
                 bottom: y2,
                 right: x2
             };
         }

        //////////////////////////////////////////////////////////////////////////////////////////////
        // Cell switching

        function resetActiveCell() {
            setActiveCellInternal(null,false);
        }

        function setFocus() {
            // IE tries to scroll the viewport so that the item being focused is aligned to the left border
            // IE-specific .setActive() sets the focus, but doesn't scroll
            if ($.browser.msie) {
                $canvas[0].setActive();
            }
            else {
                $canvas[0].focus();
            }
        }

        function scrollActiveCellIntoView() {
            if (activeCellNode) {
                var left = $(activeCellNode).position().left,
                    right = left + $(activeCellNode).outerWidth(),
                    scrollLeft = $viewport.scrollLeft(),
                    scrollRight = scrollLeft + $viewport.width();

                if (left < scrollLeft)
                    $viewport.scrollLeft(left);
                else if (right > scrollRight)
                    $viewport.scrollLeft(Math.min(left, right - $viewport[0].clientWidth));
            }
        }

        function setActiveCellInternal(newCell, editMode) {
            if (activeCellNode !== null) {
                makeActiveCellNormal();
                $(activeCellNode).removeClass("active");
            }

            var activeCellChanged = (activeCellNode !== newCell);
            activeCellNode = newCell;

            if (activeCellNode != null) {
                activeRow = parseInt($(activeCellNode).parent().attr("row"), 10);
                activeCell = getSiblingIndex(activeCellNode);

                $(activeCellNode).addClass("active");

                if (options.editable && editMode && isCellPotentiallyEditable(activeRow,activeCell)) {
                    clearTimeout(h_editorLoader);

                    if (options.asyncEditorLoading) {
                        h_editorLoader = setTimeout(makeActiveCellEditable, options.asyncEditorLoadDelay);
                    }
                    else {
                        makeActiveCellEditable();
                    }
                }
                else {
                      setFocus();
                }
            }
            else {
                activeRow = null;
                activeCell = null;
            }

            if (activeCellChanged) {
                scrollActiveCellIntoView();
                trigger(self.onActiveCellChanged, getActiveCell());
            }
        }

        function clearTextSelection() {
            if (document.selection && document.selection.empty) {
                document.selection.empty();
            }
            else if (window.getSelection) {
                var sel = window.getSelection();
                if (sel && sel.removeAllRanges) {
                    sel.removeAllRanges();
                }
            }
        }

        function isCellPotentiallyEditable(row,cell) {
            // is the data for this row loaded?
            if (row < getDataLength() && !getDataItem(row)) {
                return false;
            }

            // is this a special/non-data row?
            if (getDataItem(row) instanceof Slick.NonDataRow) {
                return false;
            }

            // are we in the Add New row?  can we create new from this cell?
            if (columns[cell].cannotTriggerInsert && row >= getDataLength()) {
                return false;
            }

            // does this cell have an editor?
            if (!getEditor(columns[cell])) {
                return false;
            }

            return true;
        }

        function makeActiveCellNormal() {
            if (!currentEditor) { return; }
            trigger(self.onBeforeCellEditorDestroy, {editor:currentEditor});
            currentEditor.destroy();
            currentEditor = null;

            if (activeCellNode) {
                $(activeCellNode).removeClass("editable invalid");

                if (getDataItem(activeRow)) {
                    var column = columns[activeCell];
                    activeCellNode.innerHTML = getFormatter(column)(activeRow, activeCell, getDataItem(activeRow)[column.field], column, getDataItem(activeRow));
                    invalidatePostProcessingResults(activeRow);
                }
            }

            // if there previously was text selected on a page (such as selected text in the edit cell just removed),
            // IE can't set focus to anything else correctly
            if ($.browser.msie) { clearTextSelection(); }

            getEditorLock().deactivate(editController);
        }

        function makeActiveCellEditable() {
            if (!activeCellNode) { return; }
            if (!options.editable) {
                throw "Grid : makeActiveCellEditable : should never get called when options.editable is false";
            }

            // cancel pending async call if there is one
            clearTimeout(h_editorLoader);

            if (!isCellPotentiallyEditable(activeRow,activeCell)) {
                return;
            }

            if (trigger(self.onBeforeEditCell, {row:activeRow, cell:activeCell,item:getDataItem(activeRow)}) === false) {
                setFocus();
                return;
            }

            getEditorLock().activate(editController);
            $(activeCellNode).addClass("editable");

            activeCellNode.innerHTML = "";

            var columnDef = columns[activeCell];
            var item = getDataItem(activeRow);

            currentEditor = new (getEditor(columnDef))({
                grid: self,
                gridPosition: absBox($container[0]),
                position: absBox(activeCellNode),
                container: activeCellNode,
                column: columnDef,
                item: item || {},
                commitChanges: commitEditAndSetFocus,
                cancelChanges: cancelEditAndSetFocus
            });

            if (item)
                currentEditor.loadValue(item);

            serializedEditorValue = currentEditor.serializeValue();

            if (currentEditor.position)
                handleActiveCellPositionChange();
        }

        function commitEditAndSetFocus() {
            // if the commit fails, it would do so due to a validation error
            // if so, do not steal the focus from the editor
            if (getEditorLock().commitCurrentEdit()) {
                  setFocus();

                if (options.autoEdit) {
                    navigateDown();
                }
            }
        }

        function cancelEditAndSetFocus() {
            if (getEditorLock().cancelCurrentEdit()) {
                  setFocus();
            }
        }

        function absBox(elem) {
            var box = {top:elem.offsetTop, left:elem.offsetLeft, bottom:0, right:0, width:$(elem).outerWidth(), height:$(elem).outerHeight(), visible:true};
            box.bottom = box.top + box.height;
            box.right = box.left + box.width;

            // walk up the tree
            var offsetParent = elem.offsetParent;
            while ((elem = elem.parentNode) != document.body) {
                if (box.visible && elem.scrollHeight != elem.offsetHeight && $(elem).css("overflowY") != "visible")
                    box.visible = box.bottom > elem.scrollTop && box.top < elem.scrollTop + elem.clientHeight;

                if (box.visible && elem.scrollWidth != elem.offsetWidth && $(elem).css("overflowX") != "visible")
                    box.visible = box.right > elem.scrollLeft && box.left < elem.scrollLeft + elem.clientWidth;

                box.left -= elem.scrollLeft;
                box.top -= elem.scrollTop;

                if (elem === offsetParent) {
                    box.left += elem.offsetLeft;
                    box.top += elem.offsetTop;
                    offsetParent = elem.offsetParent;
                }

                box.bottom = box.top + box.height;
                box.right = box.left + box.width;
            }

            return box;
        }

        function getActiveCellPosition(){
            return absBox(activeCellNode);
        }

        function getGridPosition(){
            return absBox($container[0])
        }

        function handleActiveCellPositionChange() {
            if (!activeCellNode) return;
            var cellBox;

            trigger(self.onActiveCellPositionChanged, {});

            if (currentEditor) {
                cellBox = cellBox || getActiveCellPosition();
                if (currentEditor.show && currentEditor.hide) {
                    if (!cellBox.visible)
                        currentEditor.hide();
                    else
                        currentEditor.show();
                }

                if (currentEditor.position)
                    currentEditor.position(cellBox);
            }
        }

        function getCellEditor() {
            return currentEditor;
        }

        function getActiveCell() {
            if (!activeCellNode)
                return null;
            else
                return {row: activeRow, cell: activeCell};
        }

        function getActiveCellNode() {
            return activeCellNode;
        }

        function scrollRowIntoView(row, doPaging) {
            var rowAtTop = row * options.rowHeight;
            var rowAtBottom = (row + 1) * options.rowHeight - viewportH + (viewportHasHScroll?scrollbarDimensions.height:0);

            // need to page down?
            if ((row + 1) * options.rowHeight > scrollTop + viewportH + offset) {
                scrollTo(doPaging ? rowAtTop : rowAtBottom);
                render();
            }

            // or page up?
            else if (row * options.rowHeight < scrollTop + offset) {
                scrollTo(doPaging ? rowAtBottom : rowAtTop);
                render();
            }
        }

        function gotoDir(dy, dx, rollover) {
            if (!activeCellNode || !options.enableCellNavigation) { return; }
            if (!getEditorLock().commitCurrentEdit()) { return; }

            function selectableCellFilter() {
                return !columns[getSiblingIndex(this)].unselectable
            }

            var nextRow = rowsCache[activeRow + dy];
            var nextCell = (nextRow && activeCell + dx >= 0)
                    ? $(nextRow).children().eq(activeCell+dx).filter(selectableCellFilter)
                    : null;

            if (nextCell && !nextCell.length) {
                var nodes = $(nextRow).children()
                        .filter(function(index) { return (dx>0) ? index > activeCell + dx : index < activeCell + dx })
                        .filter(selectableCellFilter);

                if (nodes && nodes.length) {
                nextCell = (dx>0)
                            ? nodes.eq(0)
                            : nodes.eq(nodes.length-1);
                }
            }

            if (rollover && dy === 0 && !(nextRow && nextCell && nextCell.length)) {
                if (!nextCell || !nextCell.length) {
                    nextRow = rowsCache[activeRow + dy + ((dx>0)?1:-1)];
                    var nodes = $(nextRow).children().filter(selectableCellFilter);
                    if (dx > 0) {
                        nextCell = nextRow
                                ? nodes.eq(0)
                                : null;
                    }
                    else {
                        nextCell = nextRow
                                ? nodes.eq(nodes.length-1)
                                : null;
                    }
                }
            }

            if (nextRow && nextCell && nextCell.length) {
                // if selecting the 'add new' row, start editing right away
                var row = parseInt($(nextRow).attr("row"), 10);
                var isAddNewRow = (row == getDataLength());
                scrollRowIntoView(row,!isAddNewRow);
                setActiveCellInternal(nextCell[0], isAddNewRow || options.autoEdit);

                // if no editor was created, set the focus back on the grid
                if (!currentEditor) {
                      setFocus();
                }
            }
            else {
                  setFocus();
            }
        }

        function getCellNode(row, cell) {
            if (rowsCache[row]) {
                return $(rowsCache[row]).children().eq(cell)[0];
            }
            return null;
        }

        function setActiveCell(row, cell) {
            if (row > getDataLength() || row < 0 || cell >= columns.length || cell < 0) {
                return;
            }

            if (!options.enableCellNavigation) {
                return;
            }

            scrollRowIntoView(row,false);
            setActiveCellInternal(getCellNode(row,cell),false);
        }

        function canCellBeSelected(row,cell) {
            return row < getDataLength()
                    && row >= 0
                    && cell < columns.length
                    && cell >= 0
                    && !columns[cell].unselectable
                    && !(getDataItem(row) instanceof Slick.NonDataRow);
        }

        function gotoCell(row, cell, forceEdit) {
            if (row > getDataLength() || row < 0 || cell >= columns.length || cell < 0) { return; }
            if (!options.enableCellNavigation || columns[cell].unselectable) { return; }

            if (!getEditorLock().commitCurrentEdit()) { return; }

            scrollRowIntoView(row,false);

            var newCell = null;
            if (!columns[cell].unselectable) {
                newCell = getCellNode(row,cell);
            }

            // if selecting the 'add new' row, start editing right away
            setActiveCellInternal(newCell, forceEdit || (row === getDataLength()) || options.autoEdit);

            // if no editor was created, set the focus back on the grid
            if (!currentEditor) {
                  setFocus();
            }
        }

        function navigateUp() {
            gotoDir(-1, 0, false);
        }

        function navigateDown() {
            gotoDir(1, 0, false);
        }

        function navigateLeft() {
            gotoDir(0, -1, false);
        }

        function navigateRight() {
            gotoDir(0, 1, false);
        }

        function navigatePrev() {
            gotoDir(0, -1, true);
        }

        function navigateNext() {
            gotoDir(0, 1, true);
        }

        //////////////////////////////////////////////////////////////////////////////////////////////
        // IEditor implementation for the editor lock

        function commitCurrentEdit() {
            var item = getDataItem(activeRow);
            var column = columns[activeCell];

            if (currentEditor) {
                if (currentEditor.isValueChanged()) {
                    var validationResults = currentEditor.validate();

                    if (validationResults.valid) {
                        if (activeRow < getDataLength()) {
                            var editCommand = {
                                row: activeRow,
                                cell: activeCell,
                                editor: currentEditor,
                                serializedValue: currentEditor.serializeValue(),
                                prevSerializedValue: serializedEditorValue,
                                execute: function() {
                                    this.editor.applyValue(item,this.serializedValue);
                                    updateRow(this.row);
                                },
                                undo: function() {
                                    this.editor.applyValue(item,this.prevSerializedValue);
                                    updateRow(this.row);
                                }
                            };

                            if (options.editCommandHandler) {
                                makeActiveCellNormal();
                                options.editCommandHandler(item,column,editCommand);

                            }
                            else {
                                editCommand.execute();
                                makeActiveCellNormal();
                            }

                            trigger(self.onCellChange, {
                                row: activeRow,
                                cell: activeCell,
                                item: item
                            });
                        }
                        else {
                            var newItem = {};
                            currentEditor.applyValue(newItem,currentEditor.serializeValue());
                            makeActiveCellNormal();
                            trigger(self.onAddNewRow, {item:newItem, column:column});
                        }

                        // check whether the lock has been re-acquired by event handlers
                        return !getEditorLock().isActive();
                    }
                    else {
                        // TODO: remove and put in onValidationError handlers in examples
                        $(activeCellNode).addClass("invalid");
                        $(activeCellNode).stop(true,true).effect("highlight", {color:"red"}, 300);

                        trigger(self.onValidationError, {
                            cellNode: activeCellNode,
                            validationResults: validationResults,
                            row: activeRow,
                            cell: activeCell,
                            column: column
                        });

                        currentEditor.focus();
                        return false;
                    }
                }

                makeActiveCellNormal();
            }
            return true;
        }

        function cancelCurrentEdit() {
            makeActiveCellNormal();
            return true;
        }

        function rowsToRanges(rows) {
            var ranges = [];
            var lastCell = columns.length - 1;
            for (var i = 0; i < rows.length; i++) {
                ranges.push(new Slick.Range(rows[i], 0, rows[i], lastCell));
            }
            return ranges;
        }

        function getSelectedRows() {
            if (!selectionModel) {
                throw "Selection model is not set";
            }
            return selectedRows;
        }

        function setSelectedRows(rows) {
            if (!selectionModel) {
                throw "Selection model is not set";
            }
            selectionModel.setSelectedRanges(rowsToRanges(rows));
        }


        //////////////////////////////////////////////////////////////////////////////////////////////
        // Debug

        this.debug = function() {
            var s = "";

            s += ("\n" + "counter_rows_rendered:  " + counter_rows_rendered);
            s += ("\n" + "counter_rows_removed:  " + counter_rows_removed);
            s += ("\n" + "renderedRows:  " + renderedRows);
            s += ("\n" + "numVisibleRows:  " + numVisibleRows);
            s += ("\n" + "maxSupportedCssHeight:  " + maxSupportedCssHeight);
            s += ("\n" + "n(umber of pages):  " + n);
            s += ("\n" + "(current) page:  " + page);
            s += ("\n" + "page height (ph):  " + ph);
            s += ("\n" + "scrollDir:  " + scrollDir);

            alert(s);
        };

        // a debug helper to be able to access private members
        this.eval = function(expr) {
            return eval(expr);
        };

        //////////////////////////////////////////////////////////////////////////////////////////////
        // Public API

        $.extend(this, {
            "slickGridVersion": "2.0a1",

            // Events
            "onScroll":                     new Slick.Event(),
            "onSort":                       new Slick.Event(),
            "onHeaderContextMenu":          new Slick.Event(),
            "onHeaderClick":                new Slick.Event(),
            "onMouseEnter":                 new Slick.Event(),
            "onMouseLeave":                 new Slick.Event(),
            "onClick":                      new Slick.Event(),
            "onDblClick":                   new Slick.Event(),
            "onContextMenu":                new Slick.Event(),
            "onKeyDown":                    new Slick.Event(),
            "onAddNewRow":                  new Slick.Event(),
            "onValidationError":            new Slick.Event(),
            "onViewportChanged":            new Slick.Event(),
            "onColumnsReordered":           new Slick.Event(),
            "onColumnsResized":             new Slick.Event(),
            "onCellChange":                 new Slick.Event(),
            "onBeforeEditCell":             new Slick.Event(),
            "onBeforeCellEditorDestroy":    new Slick.Event(),
            "onBeforeDestroy":              new Slick.Event(),
            "onActiveCellChanged":          new Slick.Event(),
            "onActiveCellPositionChanged":  new Slick.Event(),
            "onDragInit":                   new Slick.Event(),
            "onDragStart":                  new Slick.Event(),
            "onDrag":                       new Slick.Event(),
            "onDragEnd":                    new Slick.Event(),
            "onSelectedRowsChanged":        new Slick.Event(),

            // Methods
            "registerPlugin":               registerPlugin,
            "unregisterPlugin":             unregisterPlugin,
            "getColumns":                   getColumns,
            "setColumns":                   setColumns,
            "getColumnIndex":               getColumnIndex,
            "updateColumnHeader":           updateColumnHeader,
            "setSortColumn":                setSortColumn,
            "autosizeColumns":              autosizeColumns,
            "getOptions":                   getOptions,
            "setOptions":                   setOptions,
            "getData":                      getData,
            "getDataLength":                getDataLength,
            "getDataItem":                  getDataItem,
            "setData":                      setData,
            "getSelectionModel":            getSelectionModel,
            "setSelectionModel":            setSelectionModel,
            "getSelectedRows":              getSelectedRows,
            "setSelectedRows":              setSelectedRows,

            "render":                       render,
            "invalidate":                   invalidate,
            "invalidateRow":                invalidateRow,
            "invalidateRows":               invalidateRows,
            "invalidateAllRows":            invalidateAllRows,
            "updateCell":                   updateCell,
            "updateRow":                    updateRow,
            "getViewport":                  getVisibleRange,
            "resizeCanvas":                 resizeCanvas,
            "updateRowCount":               updateRowCount,
            "scrollRowIntoView":            scrollRowIntoView,
            "getCanvasNode":                getCanvasNode,

            "getCellFromPoint":             getCellFromPoint,
            "getCellFromEvent":             getCellFromEvent,
            "getActiveCell":                getActiveCell,
            "setActiveCell":                setActiveCell,
            "getActiveCellNode":            getActiveCellNode,
            "getActiveCellPosition":        getActiveCellPosition,
            "resetActiveCell":              resetActiveCell,
            "editActiveCell":               makeActiveCellEditable,
            "getCellEditor":                getCellEditor,
            "getCellNode":                  getCellNode,
            "getCellNodeBox":               getCellNodeBox,
            "canCellBeSelected":            canCellBeSelected,
            "navigatePrev":                 navigatePrev,
            "navigateNext":                 navigateNext,
            "navigateUp":                   navigateUp,
            "navigateDown":                 navigateDown,
            "navigateLeft":                 navigateLeft,
            "navigateRight":                navigateRight,
            "gotoCell":                     gotoCell,
            "getTopPanel":                  getTopPanel,
            "showTopPanel":                 showTopPanel,
            "hideTopPanel":                 hideTopPanel,
            "showHeaderRowColumns":         showHeaderRowColumns,
            "hideHeaderRowColumns":         hideHeaderRowColumns,
            "getHeaderRow":                 getHeaderRow,
            "getHeaderRowColumn":           getHeaderRowColumn,
            "getGridPosition":              getGridPosition,
            "flashCell":                    flashCell,
            "addCellCssStyles":             addCellCssStyles,
            "setCellCssStyles":             setCellCssStyles,
            "removeCellCssStyles":          removeCellCssStyles,

            "destroy":                      destroy,

            // IEditor implementation
            "getEditorLock":                getEditorLock,
            "getEditController":            getEditController
        });

        init();
    }
}(jQuery));