SimpleAjaxUploader.js

/**
 * Simple Ajax Uploader
 * Version 2.5.2
 * https://github.com/LPology/Simple-Ajax-Uploader
 *
 * Copyright 2012-2016 LPology, LLC
 * Released under the MIT license
 */

;(function( global, factory ) {
    /*globals define, module */
    if ( typeof define === 'function' && define.amd ) {
        define( function() {
            return factory( global );
        });

    } else if ( typeof module === 'object' && module.exports ) {
        module.exports = factory( global );

    } else {
        global.ss = factory( global );
    }

}( typeof window !== 'undefined' ? window : this, function( window ) {

var ss = window.ss || {},

    // ss.trim()
    rLWhitespace = /^\s+/,
    rTWhitespace = /\s+$/,

    // ss.getUID
    uidReplace = /[xy]/g,

    // ss.getFilename()
    rPath = /.*(\/|\\)/,

    // ss.getExt()
    rExt = /.*[.]/,

    // ss.hasClass()
    rHasClass = /[\t\r\n]/g,

    // Check for Safari -- it doesn't like multi file uploading. At all.
    // http://stackoverflow.com/a/9851769/1091949
    isSafari = Object.prototype.toString.call( window.HTMLElement ).indexOf( 'Constructor' ) > 0,

    isIE7 = ( navigator.userAgent.indexOf('MSIE 7') !== -1 ),

    // Check whether XHR uploads are supported
    input = document.createElement( 'input' ),

    XhrOk;

input.type = 'file';

XhrOk = ( 'multiple' in input &&
          typeof File !== 'undefined' &&
          typeof ( new XMLHttpRequest() ).upload !== 'undefined' );


/**
* Converts object to query string
*/
ss.obj2string = function( obj, prefix ) {
    "use strict";

    var str = [];

    for ( var prop in obj ) {
        if ( obj.hasOwnProperty( prop ) ) {
            var k = prefix ? prefix + '[' + prop + ']' : prop, v = obj[prop];
            str.push( typeof v === 'object' ?
                        ss.obj2string( v, k ) :
                        encodeURIComponent( k ) + '=' + encodeURIComponent( v ) );
        }
    }

    return str.join( '&' );
};

/**
* Copies all missing properties from second object to first object
*/
ss.extendObj = function( first, second ) {
    "use strict";

    for ( var prop in second ) {
        if ( second.hasOwnProperty( prop ) ) {
            first[prop] = second[prop];
        }
    }
};

ss.addEvent = function( elem, type, fn ) {
    "use strict";

    if ( elem.addEventListener ) {
        elem.addEventListener( type, fn, false );

    } else {
        elem.attachEvent( 'on' + type, fn );
    }
    return function() {
        ss.removeEvent( elem, type, fn );
    };
};

ss.removeEvent = document.removeEventListener ?
    function( elem, type, fn ) {
        if ( elem.removeEventListener ) {
            elem.removeEventListener( type, fn, false );
        }
    } :
    function( elem, type, fn ) {
        var name = 'on' + type;

        if ( typeof elem[ name ] === 'undefined' ) {
            elem[ name ] = null;
        }

        elem.detachEvent( name, fn );
    };

ss.newXHR = function() {
    "use strict";

    if ( typeof XMLHttpRequest !== 'undefined' ) {
        return new window.XMLHttpRequest();

    } else if ( window.ActiveXObject ) {
        try {
            return new window.ActiveXObject( 'Microsoft.XMLHTTP' );
        } catch ( err ) {
            return false;
        }
    }
};

ss.encodeUTF8 = function( str ) {
    "use strict";
    /*jshint nonstandard:true*/
    return unescape( encodeURIComponent( str ) );
};

ss.getIFrame = function() {
    "use strict";

    var id = ss.getUID(),
        iframe;

    // IE7 can only create an iframe this way, all others are the other way
    if ( isIE7 ) {
        iframe = document.createElement('<iframe src="javascript:false;" name="' + id + '">');

    } else {
        iframe = document.createElement('iframe');
        /*jshint scripturl:true*/
        iframe.src = 'javascript:false;';
        iframe.name = id;
    }

    iframe.style.display = 'none';
    iframe.id = id;
    return iframe;
};

ss.getForm = function( opts ) {
    "use strict";

    var form = document.createElement('form');

    form.encoding = 'multipart/form-data'; // IE
    form.enctype = 'multipart/form-data';
    form.style.display = 'none';

    for ( var prop in opts ) {
        if ( opts.hasOwnProperty( prop ) ) {
            form[prop] = opts[prop];
        }
    }

    return form;
};

ss.getHidden = function( name, value ) {
    "use strict";

    var input = document.createElement( 'input' );

    input.type = 'hidden';
    input.name = name;
    input.value = value;
    return input;
};

/**
* Parses a JSON string and returns a Javascript object
* Borrowed from www.jquery.com
*/
ss.parseJSON = function( data ) {
    "use strict";
    /*jshint evil:true*/

    if ( !data ) {
        return false;
    }

    data = ss.trim( data + '' );

    if ( window.JSON && window.JSON.parse ) {
        try {
            // Support: Android 2.3
            // Workaround failure to string-cast null input
            return window.JSON.parse( data + '' );
        } catch ( err ) {
            return false;
        }
    }

    var rvalidtokens = /(,)|(\[|{)|(}|])|"(?:[^"\\\r\n]|\\["\\\/bfnrt]|\\u[\da-fA-F]{4})*"\s*:?|true|false|null|-?(?!0\d)\d+(?:\.\d+|)(?:[eE][+-]?\d+|)/g,
        depth = null,
        requireNonComma;

    // Guard against invalid (and possibly dangerous) input by ensuring that nothing remains
    // after removing valid tokens
    return data && !ss.trim( data.replace( rvalidtokens, function( token, comma, open, close ) {

        // Force termination if we see a misplaced comma
        if ( requireNonComma && comma ) {
            depth = 0;
        }

        // Perform no more replacements after returning to outermost depth
        if ( depth === 0 ) {
            return token;
        }

        // Commas must not follow "[", "{", or ","
        requireNonComma = open || comma;

        // Determine new depth
        // array/object open ("[" or "{"): depth += true - false (increment)
        // array/object close ("]" or "}"): depth += false - true (decrement)
        // other cases ("," or primitive): depth += true - true (numeric cast)
        depth += !close - !open;

        // Remove this token
        return '';
    }) ) ?
        ( Function( 'return ' + data ) )() :
        false;
};

ss.getBox = function( elem ) {
    "use strict";

    var box,
        docElem,
        top = 0,
        left = 0;

    if ( elem.getBoundingClientRect ) {
        box = elem.getBoundingClientRect();
        docElem = document.documentElement;
        top = box.top + ( window.pageYOffset || docElem.scrollTop )  - ( docElem.clientTop  || 0 );
        left = box.left + ( window.pageXOffset || docElem.scrollLeft ) - ( docElem.clientLeft || 0 );

    } else {
        do {
            left += elem.offsetLeft;
            top += elem.offsetTop;
        } while ( ( elem = elem.offsetParent ) );
    }

    return {
        top: Math.round( top ),
        left: Math.round( left )
    };
};

/**
* Helper that takes object literal
* and add all properties to element.style
* @param {Element} el
* @param {Object} styles
*/
ss.addStyles = function( elem, styles ) {
    "use strict";

    for ( var name in styles ) {
        if ( styles.hasOwnProperty( name ) ) {
            elem.style[name] = styles[name];
        }
    }
};

/**
* Function places an absolutely positioned
* element on top of the specified element
* copying position and dimensions.
*/
ss.copyLayout = function( from, to ) {
    "use strict";

    var box = ss.getBox( from );

    ss.addStyles( to, {
        position: 'absolute',
        left : box.left + 'px',
        top : box.top + 'px',
        width : from.offsetWidth + 'px',
        height : from.offsetHeight + 'px'
    });
};

/**
* Generates unique ID
* Complies with RFC 4122 version 4
* http://stackoverflow.com/a/2117523/1091949
* ID begins with letter "a" to be safe for HTML elem ID/name attr (can't start w/ number)
*/
ss.getUID = function() {
    "use strict";

    /*jshint bitwise: false*/
    return 'axxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(uidReplace, function(c) {
        var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
        return v.toString(16);
    });
};

/**
* Removes white space from left and right of string
* Uses native String.trim if available
* Adapted from www.jquery.com
*/
var trim = "".trim;

ss.trim = trim && !trim.call("\uFEFF\xA0") ?
    function( text ) {
        return text === null ?
            "" :
            trim.call( text );
    } :
    function( text ) {
        return text === null ?
            "" :
            text.toString().replace( rLWhitespace, '' ).replace( rTWhitespace, '' );
    };

var arr = [];

ss.indexOf = arr.indexOf ?
    function( array, elem ) {
        return array.indexOf( elem );
    } :
    function( array, elem ) {
        for ( var i = 0, len = array.length; i < len; i++ ) {
            if ( array[i] === elem ) {
                return i;
            }
        }
        return -1;
    };

/**
* Extract file name from path
*/
ss.getFilename = function( path ) {
    "use strict";
    return path.replace( rPath, '' );
};

/**
* Get file extension
*/
ss.getExt = function( file ) {
    "use strict";
    return ( -1 !== file.indexOf( '.' ) ) ? file.replace( rExt, '' ) : '';
};

/**
* Checks whether an element is visible
*/
ss.isVisible = function( elem ) {
    "use strict";

    if ( elem.nodeType !== 1 || elem == document.body ) {
        elem = null;
        return true;
    }

    if ( elem.offsetWidth > 0 ||
         elem.offsetHeight > 0 ||
         ss.getStyle( elem, 'display' ).toLowerCase() != 'none' )
    {
        return ss.isVisible( elem.parentNode );
    }

    elem = null;
    return false;
};

ss.getStyle = function( elem, style ) {
    "use strict";

    if ( window.getComputedStyle ) {
        var cs = elem.ownerDocument.defaultView.getComputedStyle( elem, null );
        return cs.getPropertyValue( style );

    } else if ( elem.currentStyle && elem.currentStyle[ style ] ) {
        return elem.currentStyle[ style ];
    }
};

/**
* Accepts a form element and returns an object with key/value pairs for the form fields
*/
ss.getFormObj = function( form ) {
    "use strict";

    var elems = form.elements,
        ignore = ['button', 'submit', 'image', 'reset'],
        inputs = {},
        obj;

    for ( var i = 0, len = elems.length; i < len; i++ ) {
        obj = {};

        if ( elems[ i ].name && !elems[ i ].disabled && ss.indexOf( ignore, elems[ i ].type ) === -1 ) {
            if ( (elems[ i ].type == 'checkbox' || elems[ i ].type == 'radio') &&
                 !elems[ i ].checked )
            {
                continue;
            }

            obj[ elems[ i ].name ] = ss.val( elems[ i ] );
            ss.extendObj( inputs, obj );
        }
    }

    return inputs;
};

/**
* Accepts a form input element and returns its value
*/
ss.val = function( elem ) {
    "use strict";

    if ( !elem ) {
        return;
    }

    if ( elem.nodeName.toUpperCase() == 'SELECT' ) {
        var options = elem.options,
            index = elem.selectedIndex,
            one = elem.type === 'select-one' || index < 0,
            values = one ? null : [],
            value;

        for ( var i = 0, len = options.length; i < len; i++ ) {
            if ( ( options[ i ].selected || i === index ) && !options[ i ].disabled ) {
                value = !options[ i ].value ? options[ i ].text : options[ i ].value;

                if ( one ) {
                    return value;
                }

                values.push( value );
            }
        }

        return values;

    } else {
        return elem.value;
    }
};

/**
* Check whether element has a particular CSS class
* Parts borrowed from www.jquery.com
*/
ss.hasClass = function( elem, name ) {
    "use strict";

    if ( !elem || !name ) {
        return false;
    }

    return ( ' ' + elem.className + ' ' ).replace( rHasClass, ' ' ).indexOf( ' ' + name + ' ' ) >= 0;
};

/**
* Adds CSS class to an element
*/
ss.addClass = function( elem, name ) {
    "use strict";

    if ( !elem || !name ) {
        return false;
    }

    if ( !ss.hasClass( elem, name ) ) {
        elem.className += ' ' + name;
    }
};

/**
* Removes CSS class from an element
*/
ss.removeClass = (function() {
    "use strict";

    var c = {}; //cache regexps for performance

    return function( e, name ) {
        if ( !e || !name ) {
            return false;
        }

        if ( !c[name] ) {
            c[name] = new RegExp('(?:^|\\s)' + name + '(?!\\S)');
        }

        e.className = e.className.replace( c[name], '' );
    };
})();

/**
* Nulls out event handlers to prevent memory leaks in IE6/IE7
* http://javascript.crockford.com/memory/leak.html
* @param {Element} d
* @return void
*/
ss.purge = function( d ) {
    "use strict";

    var a = d.attributes, i, l, n;

    if ( a ) {
        for ( i = a.length - 1; i >= 0; i -= 1 ) {
            n = a[i].name;

            if ( typeof d[n] === 'function' ) {
                d[n] = null;
            }
        }
    }

    a = d.childNodes;

    if ( a ) {
        l = a.length;
        for ( i = 0; i < l; i += 1 ) {
            ss.purge( d.childNodes[i] );
        }
    }
};

/**
* Removes element from the DOM
*/
ss.remove = function( elem ) {
    "use strict";

    if ( elem && elem.parentNode ) {
        // null out event handlers for IE
        ss.purge( elem );
        elem.parentNode.removeChild( elem );
    }
    elem = null;
};

/**
* Accepts either a jQuery object, a string containing an element ID, or an element,
* verifies that it exists, and returns the element.
* @param {Mixed} elem
* @return {Element}
*/
ss.verifyElem = function( elem ) {
    "use strict";
    /*globals jQuery */

    if ( typeof jQuery !== 'undefined' && elem instanceof jQuery ) {
        elem = elem[0];

    } else if ( typeof elem === 'string' ) {
        if ( elem.charAt( 0 ) == '#' ) {
            elem = elem.substr( 1 );
        }
        elem = document.getElementById( elem );
    }

    if ( !elem || elem.nodeType !== 1 ) {
        return false;
    }

    if ( elem.nodeName.toUpperCase() == 'A' ) {
        elem.style.cursor = 'pointer';

        ss.addEvent( elem, 'click', function( e ) {
            if ( e && e.preventDefault ) {
                e.preventDefault();

            } else if ( window.event ) {
                window.event.returnValue = false;
            }
        });
    }

    return elem;
};

ss._options = {};

ss.uploadSetup = function( options ) {
    "use strict";
    ss.extendObj( ss._options, options );
};

ss.SimpleUpload = function( options ) {
    "use strict";

    this._opts = {
        button: '',
        url: '',
        dropzone: '',
        dragClass: '',
        form: '',
        overrideSubmit: true,
        cors: false,
        withCredentials: false,
        progressUrl: false,
        sessionProgressUrl: false,
        nginxProgressUrl: false,
        multiple: false,
        maxUploads: 3,
        queue: true,
        checkProgressInterval: 500,
        keyParamName: 'APC_UPLOAD_PROGRESS',
        sessionProgressName: 'PHP_SESSION_UPLOAD_PROGRESS',
        nginxProgressHeader: 'X-Progress-ID',
        customProgressHeaders: {},
        corsInputName: 'XHR_CORS_TARGETORIGIN',
        allowedExtensions: [],
        accept: '',
        maxSize: false,
        name: '',
        data: {},
        noParams: true,
        autoSubmit: true,
        multipart: true,
        method: 'POST',
        responseType: '',
        debug: false,
        hoverClass: '',
        focusClass: '',
        disabledClass: '',
        customHeaders: {},
        encodeHeaders: true,
        autoCalibrate: true,
        onBlankSubmit: function() {},
        onAbort: function( filename, uploadBtn, size ) {},
        onChange: function( filename, extension, uploadBtn, size, file ) {},
        onSubmit: function( filename, extension, uploadBtn, size ) {},
        onProgress: function( pct ) {},
        onUpdateFileSize: function( filesize ) {},
        onComplete: function( filename, response, uploadBtn, size ) {},
        onExtError: function( filename, extension ) {},
        onSizeError: function( filename, fileSize ) {},
        onError: function( filename, type, status, statusText, response, uploadBtn, size ) {},
        startXHR: function( filename, fileSize, uploadBtn ) {},
        endXHR: function( filename, fileSize, uploadBtn ) {},
        startNonXHR: function( filename, uploadBtn ) {},
        endNonXHR: function( filename, uploadBtn ) {}
    };

    ss.extendObj( this._opts, ss._options ); // Include any setup options
    ss.extendObj( this._opts, options ); // Then add options for this instance

    // An array of objects, each containing two items: a file and a reference
    // to the button which triggered the upload: { file: uploadFile, btn: button }
    this._queue = [];

    this._active = 0;
    this._disabled = false; // if disabled, clicking on button won't do anything
    this._maxFails = 10; // max allowed failed progress updates requests in iframe mode
    this._progKeys = {}; // contains the currently active upload ID progress keys
    this._sizeFlags = {}; // Cache progress keys after setting sizeBox for fewer trips to the DOM
    this._btns = [];

    this.addButton( this._opts.button );

    delete this._opts.button;
    this._opts.button = options = null;

    if ( this._opts.multiple === false ) {
        this._opts.maxUploads = 1;
    }

    if ( this._opts.dropzone !== '' ) {
        this.addDZ( this._opts.dropzone );
    }

    if ( this._opts.dropzone === '' && this._btns.length < 1 ) {
        throw new Error( "Invalid upload button. Make sure the element you're passing exists." );
    }

    if ( this._opts.form !== '' ) {
        this.setForm( this._opts.form );
    }

    this._createInput();
    this._manDisabled = false;
    this.enable( true );
};

ss.SimpleUpload.prototype = {

    destroy: function() {
        "use strict";

        // # of upload buttons
        var i = this._btns.length;

        // Put upload buttons back to the way we found them
        while ( i-- ) {
            // Remove event listener
            if ( this._btns[i].off ) {
                this._btns[i].off();
            }

            // Remove any lingering classes
            ss.removeClass( this._btns[i], this._opts.hoverClass );
            ss.removeClass( this._btns[i], this._opts.focusClass );
            ss.removeClass( this._btns[i], this._opts.disabledClass );

            // In case we disabled it
            this._btns[i].disabled = false;
        }

        this._killInput();

        // Set a flag to be checked in _last()
        this._destroy = true;
    },

    /**
    * Send data to browser console if debug is set to true
    */
    log: function( str ) {
        "use strict";

        if ( this._opts && this._opts.debug && window.console && window.console.log ) {
            window.console.log( '[Uploader] ' + str );
        }
    },

    /**
    * Replaces user data
    * Note that all previously set data is entirely removed and replaced
    */
    setData: function( data ) {
        "use strict";
        this._opts.data = data;
    },

    /**
    * Set or change uploader options
    * @param {Object} options
    */
    setOptions: function( options ) {
        "use strict";
        ss.extendObj( this._opts, options );
    },

    /**
    * Designate an element as an upload button
    */
    addButton: function( button ) {
        var btn;

        // An array of buttons was passed
        if ( button instanceof Array ) {

            for ( var i = 0, len = button.length; i < len; i++ ) {
                btn = ss.verifyElem( button[i] );

                if ( btn !== false ) {
                    this._btns.push( this.rerouteClicks( btn ) );

                } else {
                    this.log( 'Button with array index ' + i + ' is invalid' );
                }
            }

        // A single button was passed
        } else {
            btn = ss.verifyElem( button );

            if ( btn !== false ) {
                this._btns.push( this.rerouteClicks( btn ) );
            }
        }
    },

    /**
    * Designate an element as a drop zone
    */
    addDZ: function( dropzone ) {
        if ( !XhrOk ) {
            return;
        }

        dropzone = ss.verifyElem( dropzone );

        if ( !dropzone ) {
            this.log( 'Invalid or nonexistent element passed for drop zone' );
        } else {
            this.addDropZone( dropzone );
        }
    },

    /**
    * Designate an element as a progress bar
    * The CSS width % of the element will be updated as the upload progresses
    */
    setProgressBar: function( elem ) {
        "use strict";
        this._progBar = ss.verifyElem( elem );
    },

    /**
    * Designate an element to receive a string containing progress % during upload
    * Note: Uses innerHTML, so any existing child elements will be wiped out
    */
    setPctBox: function( elem ) {
        "use strict";
        this._pctBox = ss.verifyElem( elem );
    },

    /**
    * Designate an element to receive a string containing file size at start of upload
    * Note: Uses innerHTML, so any existing child elements will be wiped out
    */
    setFileSizeBox: function( elem ) {
        "use strict";
        this._sizeBox = ss.verifyElem( elem );
    },

    /**
    * Designate an element to be removed from DOM when upload is completed
    * Useful for removing progress bar, file size, etc. after upload
    */
    setProgressContainer: function( elem ) {
        "use strict";
        this._progBox = ss.verifyElem( elem );
    },

    /**
    * Designate an element to serve as the upload abort button
    */
    setAbortBtn: function( elem, remove ) {
        "use strict";

        this._abortBtn = ss.verifyElem( elem );
        this._removeAbort = false;

        if ( remove ) {
            this._removeAbort = true;
        }
    },

    setForm: function( form ) {
        "use strict";

        this._form = ss.verifyElem( form );

        if ( !this._form || this._form.nodeName.toUpperCase() != 'FORM' ) {
            this.log( 'Invalid or nonexistent element passed for form' );

        } else {
            var self = this;
            this._opts.autoSubmit = false;

            if ( this._opts.overrideSubmit ) {
                ss.addEvent( this._form, 'submit', function( e ) {
                    if ( e.preventDefault ) {
                        e.preventDefault();

                    } else if ( window.event ) {
                        window.event.returnValue = false;
                    }

                    if ( self._validateForm() ) {
                        self.submit();
                    }
                });

                this._form.submit = function() {
                    if ( self._validateForm() ) {
                        self.submit();
                    }
                };
            }
        }
    },

    /**
    * Returns number of files currently in queue
    */
    getQueueSize: function() {
        "use strict";
        return this._queue.length;
    },

    /**
    * Remove current file from upload queue, reset props, cycle to next upload
    */
    removeCurrent: function( id ) {
        "use strict";

        if ( id ) {
            var i = this._queue.length;

            while ( i-- ) {
                if ( this._queue[i].id === id ) {
                    this._queue.splice( i, 1 );
                    break;
                }
            }

        } else {
            this._queue.splice( 0, 1 );
        }

        this._cycleQueue();
    },

    /**
    * Clears Queue so only most recent select file is uploaded
    */
    clearQueue: function() {
        "use strict";
        this._queue.length = 0;
    },

    /**
    * Disables upload functionality
    */
    disable: function( _self ) {
        "use strict";

        var i = this._btns.length,
            nodeName;

        // _self is always true when disable() is called internally
        this._manDisabled = !_self || this._manDisabled === true ? true : false;
        this._disabled = true;

        while ( i-- ) {
            nodeName = this._btns[i].nodeName.toUpperCase();

            if ( nodeName == 'INPUT' || nodeName == 'BUTTON' ) {
                this._btns[i].disabled = true;
            }

            if ( this._opts.disabledClass !== '' ) {
                ss.addClass( this._btns[i], this._opts.disabledClass );
            }
        }

        // Hide file input
        if ( this._input && this._input.parentNode ) {
            this._input.parentNode.style.visibility = 'hidden';
        }
    },

    /**
    * Enables upload functionality
    */
    enable: function( _self ) {
        "use strict";

        // _self will always be true when enable() is called internally
        if ( !_self ) {
            this._manDisabled = false;
        }

        // Don't enable uploader if it was manually disabled
        if ( this._manDisabled === true ) {
            return;
        }

        var i = this._btns.length;

        this._disabled = false;

        while ( i-- ) {
            ss.removeClass( this._btns[i], this._opts.disabledClass );
            this._btns[i].disabled = false;
        }
    },

    /**
     * Updates invisible button position
     */
    updatePosition: function( btn ) {
        "use strict";

        btn = !btn ? this._btns[0] : btn;

        if ( btn && this._input && this._input.parentNode ) {
            ss.copyLayout( btn, this._input.parentNode );
        }

        btn = null;
    },

    rerouteClicks: function( elem ) {
        "use strict";

        var self = this;

        // ss.addEvent() returns a function to detach, which
        // allows us to call elem.off() to remove mouseover listener
        elem.off = ss.addEvent( elem, 'mouseover', function() {
            if ( self._disabled ) {
                return;
            }

            if ( !self._input ) {
                self._createInput();
            }

            self._overBtn = elem;
            ss.copyLayout( elem, self._input.parentNode );
            self._input.parentNode.style.visibility = 'visible';
        });

        if ( self._opts.autoCalibrate && !ss.isVisible( elem ) ) {
            self.log('Upload button not visible');

            var interval = function() {
                if ( ss.isVisible( elem ) ) {
                    self.log('Upload button now visible');

                    window.setTimeout(function() {
                        self.updatePosition( elem );

                        if ( self._btns.length === 1 ) {
                            self._input.parentNode.style.visibility = 'hidden';
                        }
                    }, 200);

                } else {
                    window.setTimeout( interval, 500 );
                }
            };

            window.setTimeout( interval, 500 );
        }

        return elem;
    },

    /**
    * Validates input and directs to either XHR method or iFrame method
    */
    submit: function( _, auto ) {
        "use strict";

        if ( !auto && this._queue.length < 1 ) {
            this._opts.onBlankSubmit.call( this );
            return;
        }

        if ( this._disabled ||
            this._active >= this._opts.maxUploads ||
            this._queue.length < 1 )
        {
            return;
        }

        if ( !this._checkFile( this._queue[0] ) ) {
            return;
        }

        // User returned false to cancel upload
        if ( false === this._opts.onSubmit.call( this, this._queue[0].name, this._queue[0].ext, this._queue[0].btn, this._queue[0].size ) ) {
            this.removeCurrent( this._queue[0].id );
            return;
        }

        // Increment the active upload counter
        this._active++;

        // Disable uploading if multiple file uploads are not enabled
        // or if queue is disabled and we've reached max uploads
        if ( this._opts.multiple === false ||
            this._opts.queue === false && this._active >= this._opts.maxUploads )
        {
            this.disable( true );
        }

        this._initUpload( this._queue[0] );
    }

};

ss.IframeUpload = {

    _detachEvents: {},

    _detach: function( id ) {
        if ( this._detachEvents[ id ] ) {
            this._detachEvents[ id ]();
            delete this._detachEvents[ id ];
        }
    },

    /**
    * Accepts a URI string and returns the hostname
    */
    _getHost: function( uri ) {
        var a = document.createElement( 'a' );

        a.href = uri;

        if ( a.hostname ) {
            return a.hostname.toLowerCase();
        }
        return uri;
    },

    _addFiles: function( file ) {
        var filename = ss.getFilename( file.value ),
            ext = ss.getExt( filename );

        if ( false === this._opts.onChange.call( this, filename, ext, this._overBtn, undefined, file ) ) {
            return false;
        }

        this._queue.push({
            id: ss.getUID(),
            file: file,
            name: filename,
            ext: ext,
            btn: this._overBtn,
            size: null
        });

        return true;
    },

    /**
    * Handles uploading with iFrame
    */
    _uploadIframe: function( fileObj, progBox, sizeBox, progBar, pctBox, abortBtn, removeAbort ) {
        "use strict";

        var self = this,
            opts = this._opts,
            key = ss.getUID(),
            iframe = ss.getIFrame(),
            form,
            url,
            msgLoaded = false,
            iframeLoaded = false,
            cancel;

        if ( opts.noParams === true ) {
            url = opts.url;

        } else {
            // If we're using Nginx Upload Progress Module, append upload key to the URL
            // Also, preserve query string if there is one
            url = !opts.nginxProgressUrl ?
                    opts.url :
                    url + ( ( url.indexOf( '?' ) > -1 ) ? '&' : '?' ) +
                          encodeURIComponent( opts.nginxProgressHeader ) + '=' + encodeURIComponent( key );
        }

        form = ss.getForm({
            action: url,
            target: iframe.name,
            method: opts.method
        });

        opts.onProgress.call( this, 0 );

        if ( pctBox ) {
            pctBox.innerHTML = '0%';
        }

        if ( progBar ) {
            progBar.style.width = '0%';
        }

        // For CORS, add a listener for the "message" event, which will be
        // triggered by the Javascript snippet in the server response
        if ( opts.cors ) {
            var msgId = ss.getUID();

            self._detachEvents[ msgId ] = ss.addEvent( window, 'message', function( event ) {
                // Make sure event.origin matches the upload URL
                if ( self._getHost( event.origin ) != self._getHost( opts.url ) ) {
                    self.log('Non-matching origin: ' + event.origin);
                    return;
                }

                msgLoaded = true;
                self._detach( msgId );
                opts.endNonXHR.call( self, fileObj.name, fileObj.btn );
                self._finish( fileObj,  '', '', event.data, sizeBox, progBox, pctBox, abortBtn, removeAbort );
            });
        }

        self._detachEvents[ iframe.id ] = ss.addEvent( iframe, 'load', function() {
            self._detach( iframe.id );

            if ( opts.sessionProgressUrl ) {
                form.appendChild( ss.getHidden( opts.sessionProgressName, key ) );
            }

            // PHP APC upload progress key field must come before the file field
            else if ( opts.progressUrl ) {
                form.appendChild( ss.getHidden( opts.keyParamName, key ) );
            }

            if ( self._form ) {
                ss.extendObj( opts.data, ss.getFormObj( self._form ) );
            }

            // Get additional data after startNonXHR() in case setData() was called prior to submitting
            for ( var prop in opts.data ) {
                if ( opts.data.hasOwnProperty( prop ) ) {
                    form.appendChild( ss.getHidden( prop, opts.data[prop] ) );
                }
            }

            // Add a field (default name: "XHR_CORS_TRARGETORIGIN") to tell server this is a CORS request
            // Value of the field is targetOrigin parameter of postMessage(message, targetOrigin)
            if ( opts.cors ) {
                form.appendChild( ss.getHidden( opts.corsInputName, window.location.href ) );
            }

            form.appendChild( fileObj.file );

            self._detachEvents[ fileObj.id ] = ss.addEvent( iframe, 'load', function() {
                if ( !iframe || !iframe.parentNode || iframeLoaded ) {
                    return;
                }

                self._detach( fileObj.id );
                iframeLoaded = true;

                delete self._progKeys[ key ];
                delete self._sizeFlags[ key ];

                if ( abortBtn ) {
                    ss.removeEvent( abortBtn, 'click', cancel );
                }

                // After a CORS response, we wait briefly for the "message" event to finish,
                // during which time the msgLoaded var will be set to true, signalling success.
                // If iframe loads without "message" event, we assume there was an error
                if ( opts.cors ) {
                    window.setTimeout(function() {
                        ss.remove( iframe );

                        // If msgLoaded has not been set to true after "message" event fires, we
                        // infer that an error must have occurred and respond accordingly
                        if ( !msgLoaded ) {
                            self._errorFinish( fileObj, '', '', false, 'error', progBox, sizeBox, pctBox, abortBtn, removeAbort );
                        }

                        fileObj = opts = key = iframe = sizeBox = progBox = pctBox = abortBtn = removeAbort = null;
                    }, 600);
                }

                // Non-CORS upload
                else {
                    try {
                        var doc = iframe.contentDocument ? iframe.contentDocument : iframe.contentWindow.document,
                            response = doc.body.innerHTML;

                        ss.remove( iframe );
                        iframe = null;

                        opts.endNonXHR.call( self, fileObj.name, fileObj.btn );

                        // No way to get status and statusText for an iframe so return empty strings
                        self._finish( fileObj, '', '', response, sizeBox, progBox, pctBox, abortBtn, removeAbort );

                    } catch ( e ) {
                        self._errorFinish( fileObj, '', e.message, false, 'error', progBox, sizeBox, pctBox, abortBtn, removeAbort );
                    }

                    fileObj = opts = key = sizeBox = progBox = pctBox = null;
                }
            });// end load

            if ( abortBtn ) {
                cancel = function() {
                    ss.removeEvent( abortBtn, 'click', cancel );

                    delete self._progKeys[key];
                    delete self._sizeFlags[key];

                    if ( iframe ) {
                        iframeLoaded = true;
                        self._detach( fileObj.id );

                        try {
                            if ( iframe.contentWindow.document.execCommand ) {
                                iframe.contentWindow.document.execCommand('Stop');
                            }
                        } catch( err ) {}

                        try {
                            iframe.src = 'javascript'.concat(':false;');
                        } catch( err ) {}

                        window.setTimeout(function() {
                            ss.remove( iframe );
                            iframe = null;
                        }, 1);
                    }

                    self.log('Upload aborted');
                    opts.onAbort.call( self, fileObj.name, fileObj.btn, fileObj.size );
                    self._last( sizeBox, progBox, pctBox, abortBtn, removeAbort );
                };

                ss.addEvent( abortBtn, 'click', cancel );
            }

            self.log( 'Commencing upload using iframe' );
            form.submit();

            // Remove form and begin next upload
            window.setTimeout(function() {
                ss.remove( form );
                form = null;
                self.removeCurrent( fileObj.id );
            }, 1);

            if ( self._hasProgUrl ) {
                // Add progress key to active key array
                self._progKeys[key] = 1;

                window.setTimeout( function() {
                    self._getProg( key, progBar, sizeBox, pctBox, 1 );
                    progBar = sizeBox = pctBox = null;
                }, 600 );
            }

        });// end load

        document.body.appendChild( form );
        document.body.appendChild( iframe );
    },

    /**
    * Retrieves upload progress updates from the server
    * (For fallback upload progress support)
    */
    _getProg: function( key, progBar, sizeBox, pctBox, counter ) {
        "use strict";

        var self = this,
            opts = this._opts,
            time = new Date().getTime(),
            xhr,
            url,
            callback;

        if ( !key ) {
            return;
        }

        // Nginx Upload Progress Module
        if ( opts.nginxProgressUrl ) {
            url = opts.nginxProgressUrl + '?' +
                  encodeURIComponent( opts.nginxProgressHeader ) + '=' + encodeURIComponent( key ) +
                  '&_=' + time;
        }

        else if ( opts.sessionProgressUrl ) {
            url = opts.sessionProgressUrl;
        }

        // PHP APC upload progress
        else if ( opts.progressUrl ) {
            url = opts.progressUrl +
            '?progresskey=' + encodeURIComponent( key ) +
            '&_=' + time;
        }

        callback = function() {
            var response,
                size,
                pct,
                status,
                statusText;

            try {
                // XDR doesn't have readyState so we just assume that it finished correctly
                if ( callback && ( opts.cors || xhr.readyState === 4 ) ) {
                    callback = undefined;
                    xhr.onreadystatechange = function() {};

                    try {
                        statusText = xhr.statusText;
                        status = xhr.status;
                    } catch( e ) {
                        statusText = '';
                        status = '';
                    }

                    // XDR also doesn't have status, so just assume that everything is fine
                    if ( opts.cors || ( status >= 200 && status < 300 ) ) {
                        response = ss.parseJSON( xhr.responseText );

                        if ( response === false ) {
                            self.log( 'Error parsing progress response (expecting JSON)' );
                            return;
                        }

                        // Handle response if using Nginx Upload Progress Module
                        if ( opts.nginxProgressUrl ) {

                            if ( response.state == 'uploading' ) {
                                size = parseInt( response.size, 10 );
                                if ( size > 0 ) {
                                    pct = Math.round( ( parseInt( response.received, 10 ) / size ) * 100 );
                                    size = Math.round( size / 1024 ); // convert to kilobytes
                                }

                            } else if ( response.state == 'done' ) {
                                pct = 100;

                            } else if ( response.state == 'error' ) {
                                self.log( 'Error requesting upload progress: ' + response.status );
                                return;
                            }
                        }

                        // Handle response if using PHP APC
                        else if ( opts.sessionProgressUrl || opts.progressUrl ) {
                            if ( response.success === true ) {
                                size = parseInt( response.size, 10 );
                                pct = parseInt( response.pct, 10 );
                            }
                        }

                        // Update progress bar width
                        if ( pct ) {
                            if ( pctBox ) {
                                pctBox.innerHTML = pct + '%';
                            }

                            if ( progBar ) {
                                progBar.style.width = pct + '%';
                            }

                            opts.onProgress.call( self, pct );
                        }

                        if ( size && !self._sizeFlags[key] ) {
                            if ( sizeBox ) {
                                sizeBox.innerHTML = size + 'K';
                            }

                            self._sizeFlags[key] = 1;
                            opts.onUpdateFileSize.call( self, size );
                        }

                        // Stop attempting progress checks if we keep failing
                        if ( !pct &&
                             !size &&
                             counter >= self._maxFails )
                        {
                            counter++;
                            self.log( 'Failed progress request limit reached. Count: ' + counter );
                            return;
                        }

                        // Begin countdown until next progress update check
                        if ( pct < 100 && self._progKeys[key] ) {
                            window.setTimeout( function() {
                                self._getProg( key, progBar, sizeBox, pctBox, counter );

                                key = progBar = sizeBox = pctBox = counter = null;
                            }, opts.checkProgressInterval );
                        }

                        // We didn't get a 2xx status so don't continue sending requests
                    } else {
                        delete self._progKeys[key];
                        self.log( 'Error requesting upload progress: ' + status + ' ' + statusText );
                    }

                    xhr = size = pct = status = statusText = response = null;
                }

            } catch( e ) {
                self.log( 'Error requesting upload progress: ' + e.message );
            }
        };

        // CORS requests in IE8 and IE9 must use XDomainRequest
        if ( opts.cors && !opts.sessionProgressUrl ) {

            if ( window.XDomainRequest ) {
                xhr = new window.XDomainRequest();
                xhr.open( 'GET', url, true );
                xhr.onprogress = xhr.ontimeout = function() {};
                xhr.onload = callback;

                xhr.onerror = function() {
                    delete self._progKeys[key];
                    key = null;
                    self.log('Error requesting upload progress');
                };

                // IE7 or some other dinosaur -- just give up
            } else {
                return;
            }

        } else {
            var method = !opts.sessionProgressUrl ? 'GET' : 'POST',
                headers = {},
                params;

            xhr = ss.newXHR();
            xhr.onreadystatechange = callback;
            xhr.open( method, url, true );

            // PHP session progress updates must be a POST request
            if ( opts.sessionProgressUrl ) {
                params = encodeURIComponent( opts.sessionProgressName ) + '=' + encodeURIComponent( key );
                headers['Content-Type'] = 'application/x-www-form-urlencoded';
            }

            // Set the upload progress header for Nginx
            if ( opts.nginxProgressUrl ) {
                headers[opts.nginxProgressHeader] = key;
            }

            headers['X-Requested-With'] = 'XMLHttpRequest';
            headers['Accept'] = 'application/json, text/javascript, */*; q=0.01';

            ss.extendObj( headers, opts.customProgressHeaders );

            for ( var i in headers ) {
                if ( headers.hasOwnProperty( i ) ) {
                    if ( opts.encodeHeaders ) {
                        xhr.setRequestHeader( i, ss.encodeUTF8( headers[ i ] + '' ) );

                    } else {
                        xhr.setRequestHeader( i, headers[ i ] + '' );
                    }
                }
            }

           xhr.send( ( opts.sessionProgressUrl &&  params ) || null );
        }
    },

    _initUpload: function( fileObj ) {
        if ( false === this._opts.startNonXHR.call( this, fileObj.name, fileObj.btn ) ) {

            if ( this._disabled ) {
                this.enable( true );
            }

            this._active--;
            return;
        }

        this._hasProgUrl = ( this._opts.progressUrl ||
                             this._opts.sessionProgressUrl ||
                             this._opts.nginxProgressUrl ) ?
                             true : false;

        this._uploadIframe( fileObj, this._progBox, this._sizeBox, this._progBar, this._pctBox, this._abortBtn, this._removeAbort );

        fileObj = this._progBox = this._sizeBox = this._progBar = this._pctBox = this._abortBtn = this._removeAbort = null;
    }
};

ss.XhrUpload = {

    _addFiles: function( files ) {
        var total = files.length,
            filename,
            ext,
            size,
            i;

        if ( !this._opts.multiple ) {
            total = 1;
        }

        for ( i = 0; i < total; i++ ) {
            filename = ss.getFilename( files[i].name );
            ext = ss.getExt( filename );
            size = Math.round( files[i].size / 1024 );

            if ( false === this._opts.onChange.call( this, filename, ext, this._overBtn, size, files[i] ) ) {
                return false;
            }

            this._queue.push({
                id: ss.getUID(),
                file: files[i],
                name: filename,
                ext: ext,
                btn: this._overBtn,
                size: size
            });
        }

        return true;
    },

    /**
    * Handles uploading with XHR
    */
    _uploadXhr: function( fileObj, url, params, headers, sizeBox, progBar, progBox, pctBox, abortBtn, removeAbort ) {
        "use strict";

        var self = this,
            opts = this._opts,
            xhr = ss.newXHR(),
            callback,
            cancel;

        // Inject file size into size box
        if ( sizeBox ) {
            sizeBox.innerHTML = fileObj.size + 'K';
        }

        // Begin progress bars at 0%
        if ( pctBox ) {
            pctBox.innerHTML = '0%';
        }

        if ( progBar ) {
            progBar.style.width = '0%';
        }

        // Borrows heavily from jQuery ajax transport
        callback = function( _, isAbort ) {
            var statusText;

            try {
                // Was never called and is aborted or complete
                if ( callback && ( isAbort || xhr.readyState === 4 ) ) {
                    callback = undefined;
                    xhr.onreadystatechange = function() {};

                    // If it's an abort
                    if ( isAbort ) {
                        // Abort it manually if needed
                        if ( xhr.readyState !== 4 ) {
                            xhr.abort();
                        }

                        opts.onAbort.call( self, fileObj.name, fileObj.btn, fileObj.size );
                        self._last( sizeBox, progBox, pctBox, abortBtn, removeAbort );

                    } else {
                        if ( abortBtn ) {
                            ss.removeEvent( abortBtn, 'click', cancel );
                        }

                        try {
                            statusText = xhr.statusText;
                        } catch( e ) {
                            // We normalize with Webkit giving an empty statusText
                            statusText = '';
                        }

                        if ( xhr.status >= 200 && xhr.status < 300 ) {
                            opts.endXHR.call( self, fileObj.name, fileObj.size, fileObj.btn );
                            self._finish( fileObj, xhr.status, statusText, xhr.responseText, sizeBox, progBox, pctBox, abortBtn, removeAbort );

                            // We didn't get a 2xx status so throw an error
                        } else {
                            self._errorFinish( fileObj, xhr.status, statusText, xhr.responseText, 'error', progBox, sizeBox, pctBox, abortBtn, removeAbort );
                        }
                    }
                }

            }
            catch ( e ) {
                if ( !isAbort ) {
                    self._errorFinish( fileObj, -1, e.message, false, 'error', progBox, sizeBox, pctBox, abortBtn, removeAbort );
                }
            }
        };

        if ( abortBtn ) {
            cancel = function() {
                ss.removeEvent( abortBtn, 'click', cancel );

                if ( callback ) {
                    callback( undefined, true );
                }
            };

            ss.addEvent( abortBtn, 'click', cancel );
        }

        xhr.onreadystatechange = callback;
        xhr.open( opts.method.toUpperCase(), url, true );
        xhr.withCredentials = !!opts.withCredentials;

        ss.extendObj( headers, opts.customHeaders );

        for ( var i in headers ) {
            if ( headers.hasOwnProperty( i ) ) {
                if ( opts.encodeHeaders ) {
                    xhr.setRequestHeader( i, ss.encodeUTF8( headers[ i ] + '' ) );

                } else {
                    xhr.setRequestHeader( i, headers[ i ] + '' );
                }
            }
        }

        ss.addEvent( xhr.upload, 'progress', function( event ) {
            if ( event.lengthComputable ) {
                var pct = Math.round( event.loaded / event.total * 100 );

                opts.onProgress.call( self, pct );

                if ( pctBox ) {
                    pctBox.innerHTML = pct + '%';
                }

                if ( progBar ) {
                    progBar.style.width = pct + '%';
                }
            }
        });

        opts.onProgress.call( this, 0 );

        if ( opts.multipart === true ) {
            var formData = new FormData();

            var hasFile = false;

            for ( var prop in params ) {
                if ( params.hasOwnProperty( prop ) ) {
                    if ( prop === opts.name && opts.noParams === true && !self._form ) {
                        hasFile = true;
                    }
                    formData.append( prop, params[prop] );
                }
            }

            if ( !hasFile ) {
                formData.append( opts.name, fileObj.file );
            }

            this.log( 'Commencing upload using multipart form' );
            xhr.send( formData );

        } else {
            this.log( 'Commencing upload using binary stream' );
            xhr.send( fileObj.file );
        }

        // Remove file from upload queue and begin next upload
        this.removeCurrent( fileObj.id );
    },

    _initUpload: function( fileObj ) {
        "use strict";

        var params = {},
            headers = {},
            url;

        // Call the startXHR() callback and stop upload if it returns false
        // We call it before _uploadXhr() in case setProgressBar, setPctBox, etc., is called
        if ( false === this._opts.startXHR.call( this, fileObj.name, fileObj.size, fileObj.btn ) ) {

            if ( this._disabled ) {
                this.enable( true );
            }

            this._active--;
            return;
        }

        headers['X-Requested-With'] = 'XMLHttpRequest';
        headers['X-File-Name'] = fileObj.name;

        if ( this._opts.responseType.toLowerCase() == 'json' ) {
            headers['Accept'] = 'application/json, text/javascript, */*; q=0.01';
        }

        if ( !this._opts.multipart ) {
            headers['Content-Type'] = 'application/octet-stream';
        }

        if ( this._form ) {
            ss.extendObj( params, ss.getFormObj( this._form ) );
        }

        // We get the any additional data here after startXHR()
        ss.extendObj( params, this._opts.data );

        // Build query string while preserving any existing parameters
        url = this._opts.noParams === true ?
                this._opts.url :
                this._opts.url + ( ( this._opts.url.indexOf( '?' ) > -1 ) ? '&' : '?' ) + ss.obj2string( params );

        this._uploadXhr( fileObj, url, params, headers, this._sizeBox, this._progBar, this._progBox, this._pctBox, this._abortBtn, this._removeAbort );

        this._sizeBox = this._progBar = this._progBox = this._pctBox = this._abortBtn = this._removeAbort = null;
    }

};

ss.DragAndDrop = {

    _dragFileCheck: function( e ) {
        if ( e.dataTransfer.types ) {
            for ( var i = 0; i < e.dataTransfer.types.length; i++ ) {
                if ( e.dataTransfer.types[i] == 'Files' ) {
                    return true;
                }
            }
        }

        return false;
    },

    addDropZone: function( elem ) {
        var self = this;
        var depthCounter = 0;

        ss.addStyles( elem, {
            'zIndex': 16777271
        });

        elem.ondragenter = function( e ) {
            e.stopPropagation();
            e.preventDefault();

            if ( !self._dragFileCheck( e ) ) {
                return false;
            }

            ss.addClass( this, self._opts.dragClass );
            depthCounter++;
            return false;
        };

        elem.ondragover = function( e ) {
            e.stopPropagation();
            e.preventDefault();
            return false;
        };

        elem.ondragend = function() {
            ss.removeClass( this, self._opts.dragClass );
            return false;
        };

        elem.ondragleave = function() {
            depthCounter--;
            if (depthCounter === 0){
              ss.removeClass( this, self._opts.dragClass );
            }
            return false;
        };

        elem.ondrop = function( e ) {
            e.stopPropagation();
            e.preventDefault();

            ss.removeClass( this, self._opts.dragClass );

            if ( !self._dragFileCheck( e ) ) {
                return;
            }

            if ( false !== self._addFiles( e.dataTransfer.files ) ) {
                self._cycleQueue();
            }
        };
    }
};

ss.extendObj( ss.SimpleUpload.prototype, {

    _createInput: function() {
        "use strict";

        var self = this,
            div = document.createElement( 'div' );

        this._input = document.createElement( 'input' );
        this._input.type = 'file';
        this._input.name = this._opts.name;

        // Don't allow multiple file selection in Safari -- it has a nasty bug
        // http://stackoverflow.com/q/7231054/1091949
        if ( XhrOk && !isSafari && this._opts.multiple ) {
            this._input.multiple = true;
        }

        // Check support for file input accept attribute
        if ( 'accept' in this._input && this._opts.accept !== '' ) {
            this._input.accept = this._opts.accept;
        }

        ss.addStyles( div, {
            'display' : 'block',
            'position' : 'absolute',
            'overflow' : 'hidden',
            'margin' : 0,
            'padding' : 0,
            'opacity' : 0,
            'direction' : 'ltr',
            'zIndex': 16777270
        });

        if ( div.style.opacity !== '0' ) {
            div.style.filter = 'alpha(opacity=0)';
        }

        ss.addStyles( this._input, {
            'position' : 'absolute',
            'right' : 0,
            'margin' : 0,
            'padding' : 0,
            'fontSize' : '480px',
            'fontFamily' : 'sans-serif',
            'cursor' : 'pointer',
            'height' : '100%',
            'zIndex': 16777270
        });

        this._input.turnOff = ss.addEvent( this._input, 'change', function() {
            if ( !self._input || self._input.value === '' ) {
                return;
            }

            if ( false === self._addFiles( XhrOk ? self._input.files : self._input ) ) {
                return;
            }

            ss.removeClass( self._overBtn, self._opts.hoverClass );
            ss.removeClass( self._overBtn, self._opts.focusClass );

            self._killInput();

            // Then create a new file input
            self._createInput();

            // Submit if autoSubmit option is true
            if ( self._opts.autoSubmit ) {
                self.submit();
            }
        });

        if ( self._opts.hoverClass !== '' ) {
            div.mouseOverOff = ss.addEvent( div, 'mouseover', function() {
                ss.addClass( self._overBtn, self._opts.hoverClass );
            });
        }

        div.mouseOutOff = ss.addEvent( div, 'mouseout', function() {
            self._input.parentNode.style.visibility = 'hidden';

            if ( self._opts.hoverClass !== '' ) {
                ss.removeClass( self._overBtn, self._opts.hoverClass );
                ss.removeClass( self._overBtn, self._opts.focusClass );
            }
        });

        if ( self._opts.focusClass !== '' ) {
            this._input.focusOff = ss.addEvent( this._input, 'focus', function() {
                ss.addClass( self._overBtn, self._opts.focusClass );
            });

            this._input.blurOff = ss.addEvent( this._input, 'blur', function() {
                ss.removeClass( self._overBtn, self._opts.focusClass );
            });
        }

        div.appendChild( this._input );
        document.body.appendChild( div );
        div = null;
    },

    /**
    * Final cleanup function after upload ends
    */
    _last: function( sizeBox, progBox, pctBox, abortBtn, removeAbort ) {
        "use strict";

        if ( sizeBox ) {
           sizeBox.innerHTML = '';
        }

        if ( pctBox ) {
            pctBox.innerHTML = '';
        }

        if ( abortBtn && removeAbort ) {
            ss.remove( abortBtn );
        }

        if ( progBox ) {
            ss.remove( progBox );
        }

        // Decrement the active upload counter
        this._active--;

        sizeBox = progBox = pctBox = abortBtn = removeAbort = null;

        if ( this._disabled ) {
            this.enable( true );
        }

        // Burn it all down if destroy() was called
        // We have to do it here after everything is finished to avoid any errors
        if ( this._destroy &&
             this._queue.length === 0 &&
             this._active === 0 )
        {
            for ( var prop in this ) {
                if ( this.hasOwnProperty( prop ) ) {
                    delete this[ prop ];
                }
            }

        // Otherwise just go to the next upload as usual
        } else {
            this._cycleQueue();
        }
    },

    /**
    * Completes upload request if an error is detected
    */
    _errorFinish: function( fileObj, status, statusText, response, errorType, progBox, sizeBox, pctBox, abortBtn, removeAbort ) {
        "use strict";

        this.log( 'Upload failed: ' + status + ' ' + statusText );
        this._opts.onError.call( this, fileObj.name, errorType, status, statusText, response, fileObj.btn, fileObj.size );
        this._last( sizeBox, progBox, pctBox, abortBtn, removeAbort );

        fileObj = status = statusText = response = errorType = sizeBox = progBox = pctBox = abortBtn = removeAbort = null;
    },

    /**
    * Completes upload request if the transfer was successful
    */
    _finish: function( fileObj, status, statusText, response, sizeBox, progBox, pctBox, abortBtn, removeAbort ) {
        "use strict";

        this.log( 'Server response: ' + response );

        if ( this._opts.responseType.toLowerCase() == 'json' ) {
            response = ss.parseJSON( response );

            if ( response === false ) {
                this._errorFinish( fileObj, status, statusText, false, 'parseerror', progBox, sizeBox, abortBtn, removeAbort );
                return;
            }
        }

        this._opts.onComplete.call( this, fileObj.name, response, fileObj.btn, fileObj.size );
        this._last( sizeBox, progBox, pctBox, abortBtn, removeAbort );
        fileObj = status = statusText = response = sizeBox = progBox = pctBox = abortBtn = removeAbort = null;
    },

    /**
    * Verifies that file is allowed
    * Checks file extension and file size if limits are set
    */
    _checkFile: function( fileObj ) {
        "use strict";

        var extOk = false,
            i = this._opts.allowedExtensions.length;

        // Only file extension if allowedExtensions is set
        if ( i > 0 ) {
            while ( i-- ) {
                if ( this._opts.allowedExtensions[i].toLowerCase() == fileObj.ext.toLowerCase() ) {
                    extOk = true;
                    break;
                }
            }

            if ( !extOk ) {
                this.removeCurrent( fileObj.id );
                this.log( 'File extension not permitted' );
                this._opts.onExtError.call( this, fileObj.name, fileObj.ext );
                return false;
            }
        }

        if ( fileObj.size &&
            this._opts.maxSize !== false &&
            fileObj.size > this._opts.maxSize )
        {
            this.removeCurrent( fileObj.id );
            this.log( fileObj.name + ' exceeds ' + this._opts.maxSize + 'K limit' );
            this._opts.onSizeError.call( this, fileObj.name, fileObj.size );
            return false;
        }

        fileObj = null;

        return true;
    },

    _killInput: function() {
        "use strict";

        if ( !this._input ) {
            return;
        }

        if ( this._input.turnOff ) {
            this._input.turnOff();
        }

        if ( this._input.focusOff ) {
            this._input.focusOff();
        }

        if ( this._input.blurOff ) {
            this._input.blurOff();
        }

        if ( this._input.parentNode.mouseOverOff ) {
            this._input.parentNode.mouseOverOff();
        }

        ss.remove( this._input.parentNode );
        delete this._input;
        this._input = null;
    },

    /**
    * Enables uploader and submits next file for upload
    */
    _cycleQueue: function() {
        "use strict";

        if ( this._queue.length > 0 && this._opts.autoSubmit ) {
            this.submit( undefined, true );
        }
    },

    _validateForm: function() {
        "use strict";

        if ( this._form.checkValidity && !this._form.checkValidity() ) {
            return false;

        } else {
            return true;
        }
    }

});

if ( XhrOk ) {
    ss.extendObj( ss.SimpleUpload.prototype, ss.XhrUpload );

} else {
    ss.extendObj( ss.SimpleUpload.prototype, ss.IframeUpload );
}

ss.extendObj( ss.SimpleUpload.prototype, ss.DragAndDrop );

return ss;

}));