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new offset method, faster and no more browser detection

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brandonaaron committed Nov 10, 2008
1 parent b64d609 commit 5c21e44fce5335cfe1bb4989006900476f2c75ca
Showing with 110 additions and 92 deletions.
  1. +75 −90 src/offset.js
  2. +24 −0 test/data/offset/body.html
  3. +11 −2 test/unit/offset.js
@@ -1,101 +1,86 @@
// The Offset Method
// Originally By Brandon Aaron, part of the Dimension Plugin
// http://jquery.com/plugins/project/dimensions
jQuery.fn.offset = function() {
var left = 0, top = 0, elem = this[0], results;

if ( elem ) with ( jQuery.browser ) {
var parent = elem.parentNode,
offsetChild = elem,
offsetParent = elem.offsetParent,
doc = elem.ownerDocument,
safari2 = safari && parseInt(version) < 522 && !/adobeair/i.test(userAgent),
css = jQuery.curCSS,
fixed = css(elem, "position") == "fixed";

// Use getBoundingClientRect if available
if ( !(mozilla && elem == document.body) && elem.getBoundingClientRect ) {
var box = elem.getBoundingClientRect();

// Add the document scroll offsets
add(box.left + Math.max(doc.documentElement.scrollLeft, doc.body.scrollLeft),
box.top + Math.max(doc.documentElement.scrollTop, doc.body.scrollTop));

// IE adds the HTML element's border, by default it is medium which is 2px
// IE 6 and 7 quirks mode the border width is overwritable by the following css html { border: 0; }
// IE 7 standards mode, the border is always 2px
// This border/offset is typically represented by the clientLeft and clientTop properties
// However, in IE6 and 7 quirks mode the clientLeft and clientTop properties are not updated when overwriting it via CSS
// Therefore this method will be off by 2px in IE while in quirksmode
add( -doc.documentElement.clientLeft, -doc.documentElement.clientTop );

// Otherwise loop through the offsetParents and parentNodes
} else {

// Initial element offsets
add( elem.offsetLeft, elem.offsetTop );

// Get parent offsets
while ( offsetParent ) {
// Add offsetParent offsets
add( offsetParent.offsetLeft, offsetParent.offsetTop );

// Mozilla and Safari > 2 does not include the border on offset parents
// However Mozilla adds the border for table or table cells
if ( mozilla && !/^t(able|d|h)$/i.test(offsetParent.tagName) || safari && !safari2 )
border( offsetParent );

// Add the document scroll offsets if position is fixed on any offsetParent
if ( !fixed && css(offsetParent, "position") == "fixed" )
fixed = true;

// Set offsetChild to previous offsetParent unless it is the body element
offsetChild = /^body$/i.test(offsetParent.tagName) ? offsetChild : offsetParent;
// Get next offsetParent
offsetParent = offsetParent.offsetParent;
if ( document.documentElement["getBoundingClientRect"] )
jQuery.fn.offset = function() {
if ( !this[0] ) return { top: 0, left: 0 };
if ( this[0] === this[0].ownerDocument.body ) return jQuery.offset.bodyOffset( this[0] );
var box = this[0].getBoundingClientRect(), doc = this[0].ownerDocument, docElem = doc.documentElement,
top = box.top + (self.pageYOffset || jQuery.boxModel && docElem.scrollTop || doc.body.scrollTop ) - docElem.clientTop,
left = box.left + (self.pageXOffset || jQuery.boxModel && docElem.scrollLeft || doc.body.scrollLeft) - docElem.clientLeft;
return { top: top, left: left };
};
else
jQuery.fn.offset = function() {
if ( !this[0] ) return { top: 0, left: 0 };
if ( this[0] === this[0].ownerDocument.body ) return jQuery.offset.bodyOffset( this[0] );
jQuery.offset.initialized || jQuery.offset.initialize();

var elem = this[0], offsetParent = elem.offsetParent, prevOffsetParent = elem,
doc = elem.ownerDocument, computedStyle, docElem = doc.documentElement,
body = doc.body, defaultView = doc.defaultView,
prevComputedStyle = defaultView.getComputedStyle(elem, null),
top = elem.offsetTop, left = elem.offsetLeft;

while ( (elem = elem.parentNode) && elem !== body && elem !== docElem ) {
computedStyle = defaultView.getComputedStyle(elem, null);
top -= elem.scrollTop, left -= elem.scrollLeft;
if ( elem === offsetParent ) {
top += elem.offsetTop, left += elem.offsetLeft;
if ( jQuery.offset.doesNotAddBorder && !(jQuery.offset.doesAddBorderForTableAndCells && /^t(able|d|h)$/i.test(elem.tagName)) )
top += parseInt( computedStyle.borderTopWidth, 10) || 0,
left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
prevOffsetParent = offsetParent, offsetParent = elem.offsetParent;
}
if ( jQuery.offset.subtractsBorderForOverflowNotVisible && computedStyle.overflow !== "visible" )
top += parseInt( computedStyle.borderTopWidth, 10) || 0,
left += parseInt( computedStyle.borderLeftWidth, 10) || 0;
prevComputedStyle = computedStyle;
}

// Get parent scroll offsets
while ( parent && parent.tagName && !/^body|html$/i.test(parent.tagName) ) {
// Remove parent scroll UNLESS that parent is inline or a table to work around Opera inline/table scrollLeft/Top bug
if ( !/^inline|table.*$/i.test(css(parent, "display")) )
// Subtract parent scroll offsets
add( -parent.scrollLeft, -parent.scrollTop );
if ( prevComputedStyle.position === "relative" || prevComputedStyle.position === "static" )
top += body.offsetTop,
left += body.offsetLeft;

// Mozilla does not add the border for a parent that has overflow != visible
if ( mozilla && css(parent, "overflow") != "visible" )
border( parent );
if ( prevComputedStyle.position === "fixed" )
top += Math.max(docElem.scrollTop, body.scrollTop),
left += Math.max(docElem.scrollLeft, body.scrollLeft);

// Get next parent
parent = parent.parentNode;
}
return { top: top, left: left };
};

// Safari <= 2 doubles body offsets with a fixed position element/offsetParent or absolutely positioned offsetChild
// Mozilla doubles body offsets with a non-absolutely positioned offsetChild
if ( (safari2 && (fixed || css(offsetChild, "position") == "absolute")) ||
(mozilla && css(offsetChild, "position") != "absolute") )
add( -doc.body.offsetLeft, -doc.body.offsetTop );
jQuery.offset = {
initialize: function() {
if ( this.initialized ) return;
var body = document.body, container = document.createElement('div'), innerDiv, checkDiv, table, rules, prop, bodyMarginTop = body.style.marginTop,
html = '<div style="position:absolute;top:0;left:0;margin:0;border:5px solid #000;padding:0;width:1px;height:1px;"><div></div></div><table style="position:absolute;top:0;left:0;margin:0;border:5px solid #000;padding:0;width:1px;height:1px;"cellpadding="0"cellspacing="0"><tr><td></td></tr></table>';

// Add the document scroll offsets if position is fixed
if ( fixed )
add(Math.max(doc.documentElement.scrollLeft, doc.body.scrollLeft),
Math.max(doc.documentElement.scrollTop, doc.body.scrollTop));
}
rules = { position: 'absolute', top: 0, left: 0, margin: 0, border: 0, width: '1px', height: '1px', visibility: 'hidden' }
for ( prop in rules ) container.style[prop] = rules[prop];

// Return an object with top and left properties
results = { top: top, left: left };
}
container.innerHTML = html;
body.insertBefore(container, body.firstChild);
innerDiv = container.firstChild, checkDiv = innerDiv.firstChild, td = innerDiv.nextSibling.firstChild.firstChild;

function border(elem) {
add( jQuery.curCSS(elem, "borderLeftWidth", true), jQuery.curCSS(elem, "borderTopWidth", true) );
}
this.doesNotAddBorder = (checkDiv.offsetTop !== 5);
this.doesAddBorderForTableAndCells = (td.offsetTop === 5);

function add(l, t) {
left += parseInt(l, 10) || 0;
top += parseInt(t, 10) || 0;
}
innerDiv.style.overflow = 'hidden', innerDiv.style.position = 'relative';
this.subtractsBorderForOverflowNotVisible = (checkDiv.offsetTop === -5);

body.style.marginTop = '1px';
this.doesNotIncludeMarginInBodyOffset = (body.offsetTop === 0);
body.style.marginTop = bodyMarginTop;

return results;
body.removeChild(container);
this.initialized = true;
},

bodyOffset: function(body) {
jQuery.offset.initialized || jQuery.offset.initialize();
var top = body.offsetTop, left = body.offsetLeft;
if ( jQuery.offset.doesNotIncludeMarginInBodyOffset )
top += parseInt( jQuery.curCSS(body, 'marginTop', true), 10 ) || 0,
left += parseInt( jQuery.curCSS(body, 'marginLeft', true), 10 ) || 0;
return { top: top, left: left };
}
};


@@ -114,11 +99,11 @@ jQuery.fn.extend({
// Subtract element margins
// note: when an element has margin: auto the offsetLeft and marginLeft
// are the same in Safari causing offset.left to incorrectly be 0
offset.top -= num( this, 'marginTop' );
offset.top -= num( this, 'marginTop' );
offset.left -= num( this, 'marginLeft' );

// Add offsetParent borders
parentOffset.top += num( offsetParent, 'borderTopWidth' );
parentOffset.top += num( offsetParent, 'borderTopWidth' );
parentOffset.left += num( offsetParent, 'borderLeftWidth' );

// Subtract the two offsets
@@ -0,0 +1,24 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8">
<title>body</title>
<style type="text/css" media="screen">
body { margin: 1px; padding: 5px; }
#marker { position: absolute; border: 2px solid #000; width: 50px; height: 50px; background: #ccc; }
</style>
<script type="text/javascript" src="../../../dist/jquery.js"></script>
<script type="text/javascript" charset="utf-8">
$(function() {
$('body').click(function() {
$('#marker').css( $(this).offset() );
return false;
});
});
</script>
</head>
<body>
<div id="marker"></div>
</body>
</html>
@@ -126,10 +126,10 @@ if ( !jQuery.browser.msie || (jQuery.browser.msie && parseInt(jQuery.browser.ver
var $w = testwin["fixed"].$;

equals( $w('#fixed-1').offset().top, 1001, "jQuery('#fixed-1').offset().top" );
equals( $w('#fixed-1').offset().left, jQuery.browser.msie ? 994 : 1001, "jQuery('#fixed-1').offset().left" );
equals( $w('#fixed-1').offset().left, 1001, "jQuery('#fixed-1').offset().left" );

equals( $w('#fixed-2').offset().top, 1021, "jQuery('#fixed-2').offset().top" );
equals( $w('#fixed-2').offset().left, jQuery.browser.msie ? 1014 : 1021, "jQuery('#fixed-2').offset().left" );
equals( $w('#fixed-2').offset().left, 1021, "jQuery('#fixed-2').offset().left" );

testwin["fixed"].close();
});
@@ -161,4 +161,13 @@ testwin("scroll", function() {
equals( $w('#scroll-1-1').offset().left, 11, "jQuery('#scroll-1-1').offset().left" );

testwin["scroll"].close();
});

testwin("body", function() {
var $w = testwin["body"].$;

equals( $w('body').offset().top, 1, "jQuery('#body').offset().top" );
equals( $w('body').offset().left, 1, "jQuery('#body').offset().left" );

testwin["body"].close();
});

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