jquery-ui/ui/widgets/sortable.js

/*!
 * jQuery UI Sortable @VERSION
 * http://jqueryui.com
 *
 * Copyright jQuery Foundation and other contributors
 * Released under the MIT license.
 * http://jquery.org/license
 */

//>>label: Sortable
//>>group: Interactions
//>>description: Enables items in a list to be sorted using the mouse.
//>>docs: http://api.jqueryui.com/sortable/
//>>demos: http://jqueryui.com/sortable/
//>>css.structure: ../../themes/base/sortable.css

( function( factory ) {
	if ( typeof define === "function" && define.amd ) {

		// AMD. Register as an anonymous module.
		define( [
			"jquery",
			"./mouse",
			"../data",
			"../ie",
			"../scroll-parent",
			"../version",
			"../widget"
		], factory );
	} else {

		// Browser globals
		factory( jQuery );
	}
}( function( $ ) {

return $.widget( "ui.sortable", $.ui.mouse, {
	version: "@VERSION",
	widgetEventPrefix: "sort",
	ready: false,
	options: {
		appendTo: "parent",
		axis: false,
		connectWith: false,
		containment: false,
		cursor: "auto",
		cursorAt: false,
		dropOnEmpty: true,
		forcePlaceholderSize: false,
		forceHelperSize: false,
		grid: false,
		handle: false,
		helper: "original",
		items: "> *",
		opacity: false,
		placeholder: false,
		revert: false,
		scroll: true,
		scrollSensitivity: 20,
		scrollSpeed: 20,
		scope: "default",
		tolerance: "intersect",
		zIndex: 1000,

		// Callbacks
		activate: null,
		beforeStop: null,
		change: null,
		deactivate: null,
		out: null,
		over: null,
		receive: null,
		remove: null,
		sort: null,
		start: null,
		stop: null,
		update: null
	},

	_isOverAxis: function( x, reference, size ) {
		return ( x >= reference ) && ( x < ( reference + size ) );
	},

	_isFloating: function( item ) {
		return ( /left|right/ ).test( item.css( "float" ) ) || ( /inline|table-cell/ ).test( item.css( "display" ) );
	},

	_create: function() {
		this.containerCache = {};
		this._addClass( "ui-sortable" );

		//Get the items
		this.refresh();

		//Let's determine the parent's offset
		this.offset = this.element.offset();

		//Initialize mouse events for interaction
		this._mouseInit();

		this._setHandleClassName();

		//We're ready to go
		this.ready = true;

	},

	_setOption: function( key, value ) {
		this._super( key, value );

		if ( key === "handle" ) {
			this._setHandleClassName();
		}
	},

	_setHandleClassName: function() {
		var that = this;
		this._removeClass( this.element.find( ".ui-sortable-handle" ), "ui-sortable-handle" );
		$.each( this.items, function() {
			that._addClass(
				this.instance.options.handle ?
					this.item.find( this.instance.options.handle ) :
					this.item,
				"ui-sortable-handle"
			);
		} );
	},

	_destroy: function() {
		this._mouseDestroy();

		for ( var i = this.items.length - 1; i >= 0; i-- ) {
			this.items[ i ].item.removeData( this.widgetName + "-item" );
		}

		return this;
	},

	_mouseCapture: function( event, overrideHandle ) {
		var currentItem = null,
			validHandle = false,
			that = this;

		if ( this.reverting ) {
			return false;
		}

		if ( this.options.disabled || this.options.type === "static" ) {
			return false;
		}

		//We have to refresh the items data once first
		this._refreshItems( event );

		//Find out if the clicked node (or one of its parents) is a actual item in this.items
		$( event.target ).parents().each( function() {
			if ( $.data( this, that.widgetName + "-item" ) === that ) {
				currentItem = $( this );
				return false;
			}
		} );
		if ( $.data( event.target, that.widgetName + "-item" ) === that ) {
			currentItem = $( event.target );
		}

		if ( !currentItem ) {
			return false;
		}
		if ( this.options.handle && !overrideHandle ) {
			$( this.options.handle, currentItem ).find( "*" ).addBack().each( function() {
				if ( this === event.target ) {
					validHandle = true;
				}
			} );
			if ( !validHandle ) {
				return false;
			}
		}

		this.currentItem = currentItem;
		this._removeCurrentsFromItems();
		return true;

	},

	_mouseStart: function( event, overrideHandle, noActivation ) {

		var i, body,
			o = this.options;

		this.currentContainer = this;

		//We only need to call refreshPositions, because the refreshItems call has been moved to mouseCapture
		this.refreshPositions();

		//Create and append the visible helper
		this.helper = this._createHelper( event );

		//Cache the helper size
		this._cacheHelperProportions();

		/*
		 * - Position generation -
		 * This block generates everything position related - it's the core of draggables.
		 */

		//Cache the margins of the original element
		this._cacheMargins();

		//Get the next scrolling parent
		this.scrollParent = this.helper.scrollParent();

		//The element's absolute position on the page minus margins
		this.offset = this.currentItem.offset();
		this.offset = {
			top: this.offset.top - this.margins.top,
			left: this.offset.left - this.margins.left
		};

		$.extend( this.offset, {
			click: { //Where the click happened, relative to the element
				left: event.pageX - this.offset.left,
				top: event.pageY - this.offset.top
			},
			parent: this._getParentOffset(),
			relative: this._getRelativeOffset() //This is a relative to absolute position minus the actual position calculation - only used for relative positioned helper
		} );

		// Only after we got the offset, we can change the helper's position to absolute
		// TODO: Still need to figure out a way to make relative sorting possible
		this.helper.css( "position", "absolute" );
		this.cssPosition = this.helper.css( "position" );

		//Generate the original position
		this.originalPosition = this._generatePosition( event );
		this.originalPageX = event.pageX;
		this.originalPageY = event.pageY;

		//Adjust the mouse offset relative to the helper if "cursorAt" is supplied
		( o.cursorAt && this._adjustOffsetFromHelper( o.cursorAt ) );

		//Cache the former DOM position
		this.domPosition = { prev: this.currentItem.prev()[ 0 ], parent: this.currentItem.parent()[ 0 ] };

		//If the helper is not the original, hide the original so it's not playing any role during the drag, won't cause anything bad this way
		if ( this.helper[ 0 ] !== this.currentItem[ 0 ] ) {
			this.currentItem.hide();
		}

		//Create the placeholder
		this._createPlaceholder();

		//Set a containment if given in the options
		if ( o.containment ) {
			this._setContainment();
		}

		if ( o.cursor && o.cursor !== "auto" ) { // cursor option
			body = this.document.find( "body" );

			// Support: IE
			this.storedCursor = body.css( "cursor" );
			body.css( "cursor", o.cursor );

			this.storedStylesheet = $( "<style>*{ cursor: " + o.cursor + " !important; }</style>" ).appendTo( body );
		}

		if ( o.opacity ) { // opacity option
			if ( this.helper.css( "opacity" ) ) {
				this._storedOpacity = this.helper.css( "opacity" );
			}
			this.helper.css( "opacity", o.opacity );
		}

		if ( o.zIndex ) { // zIndex option
			if ( this.helper.css( "zIndex" ) ) {
				this._storedZIndex = this.helper.css( "zIndex" );
			}
			this.helper.css( "zIndex", o.zIndex );
		}

		//Prepare scrolling
		if ( this.scrollParent[ 0 ] !== this.document[ 0 ] && this.scrollParent[ 0 ].tagName !== "HTML" ) {
			this.overflowOffset = this.scrollParent.offset();
		}

		//Call callbacks
		this._trigger( "start", event, this._uiHash() );

		//Recache the helper size
		if ( !this._preserveHelperProportions ) {
			this._cacheHelperProportions();
		}

		//Post "activate" events to possible containers
		if ( !noActivation ) {
			for ( i = this.containers.length - 1; i >= 0; i-- ) {
				this.containers[ i ]._trigger( "activate", event, this._uiHash( this ) );
			}
		}

		//Prepare possible droppables
		if ( $.ui.ddmanager ) {
			$.ui.ddmanager.current = this;
		}

		if ( $.ui.ddmanager && !o.dropBehaviour ) {
			$.ui.ddmanager.prepareOffsets( this, event );
		}

		this.dragging = true;

		this._addClass( this.helper, "ui-sortable-helper" );
		this._mouseDrag( event ); //Execute the drag once - this causes the helper not to be visible before getting its correct position
		return true;

	},

	_mouseDrag: function( event ) {
		var i, item, itemElement, intersection,
			o = this.options,
			scrolled = false;

		//Compute the helpers position
		this.position = this._generatePosition( event );
		this.positionAbs = this._convertPositionTo( "absolute" );

		if ( !this.lastPositionAbs ) {
			this.lastPositionAbs = this.positionAbs;
		}

		//Do scrolling
		if ( this.options.scroll ) {
			if ( this.scrollParent[ 0 ] !== this.document[ 0 ] && this.scrollParent[ 0 ].tagName !== "HTML" ) {

				if ( ( this.overflowOffset.top + this.scrollParent[ 0 ].offsetHeight ) - event.pageY < o.scrollSensitivity ) {
					this.scrollParent[ 0 ].scrollTop = scrolled = this.scrollParent[ 0 ].scrollTop + o.scrollSpeed;
				} else if ( event.pageY - this.overflowOffset.top < o.scrollSensitivity ) {
					this.scrollParent[ 0 ].scrollTop = scrolled = this.scrollParent[ 0 ].scrollTop - o.scrollSpeed;
				}

				if ( ( this.overflowOffset.left + this.scrollParent[ 0 ].offsetWidth ) - event.pageX < o.scrollSensitivity ) {
					this.scrollParent[ 0 ].scrollLeft = scrolled = this.scrollParent[ 0 ].scrollLeft + o.scrollSpeed;
				} else if ( event.pageX - this.overflowOffset.left < o.scrollSensitivity ) {
					this.scrollParent[ 0 ].scrollLeft = scrolled = this.scrollParent[ 0 ].scrollLeft - o.scrollSpeed;
				}

			} else {

				if ( event.pageY - this.document.scrollTop() < o.scrollSensitivity ) {
					scrolled = this.document.scrollTop( this.document.scrollTop() - o.scrollSpeed );
				} else if ( this.window.height() - ( event.pageY - this.document.scrollTop() ) < o.scrollSensitivity ) {
					scrolled = this.document.scrollTop( this.document.scrollTop() + o.scrollSpeed );
				}

				if ( event.pageX - this.document.scrollLeft() < o.scrollSensitivity ) {
					scrolled = this.document.scrollLeft( this.document.scrollLeft() - o.scrollSpeed );
				} else if ( this.window.width() - ( event.pageX - this.document.scrollLeft() ) < o.scrollSensitivity ) {
					scrolled = this.document.scrollLeft( this.document.scrollLeft() + o.scrollSpeed );
				}

			}

			if ( scrolled !== false && $.ui.ddmanager && !o.dropBehaviour ) {
				$.ui.ddmanager.prepareOffsets( this, event );
			}
		}

		//Regenerate the absolute position used for position checks
		this.positionAbs = this._convertPositionTo( "absolute" );

		//Set the helper position
		if ( !this.options.axis || this.options.axis !== "y" ) {
			this.helper[ 0 ].style.left = this.position.left + "px";
		}
		if ( !this.options.axis || this.options.axis !== "x" ) {
			this.helper[ 0 ].style.top = this.position.top + "px";
		}

		//Rearrange
		for ( i = this.items.length - 1; i >= 0; i-- ) {

			//Cache variables and intersection, continue if no intersection
			item = this.items[ i ];
			itemElement = item.item[ 0 ];
			intersection = this._intersectsWithPointer( item );
			if ( !intersection ) {
				continue;
			}

			// Only put the placeholder inside the current Container, skip all
			// items from other containers. This works because when moving
			// an item from one container to another the
			// currentContainer is switched before the placeholder is moved.
			//
			// Without this, moving items in "sub-sortables" can cause
			// the placeholder to jitter between the outer and inner container.
			if ( item.instance !== this.currentContainer ) {
				continue;
			}

			// Cannot intersect with itself
			// no useless actions that have been done before
			// no action if the item moved is the parent of the item checked
			if ( itemElement !== this.currentItem[ 0 ] &&
				this.placeholder[ intersection === 1 ? "next" : "prev" ]()[ 0 ] !== itemElement &&
				!$.contains( this.placeholder[ 0 ], itemElement ) &&
				( this.options.type === "semi-dynamic" ? !$.contains( this.element[ 0 ], itemElement ) : true )
			) {

				this.direction = intersection === 1 ? "down" : "up";

				if ( this.options.tolerance === "pointer" || this._intersectsWithSides( item ) ) {
					this._rearrange( event, item );
				} else {
					break;
				}

				this._trigger( "change", event, this._uiHash() );
				break;
			}
		}

		//Post events to containers
		this._contactContainers( event );

		//Interconnect with droppables
		if ( $.ui.ddmanager ) {
			$.ui.ddmanager.drag( this, event );
		}

		//Call callbacks
		this._trigger( "sort", event, this._uiHash() );

		this.lastPositionAbs = this.positionAbs;
		return false;

	},

	_mouseStop: function( event, noPropagation ) {

		if ( !event ) {
			return;
		}

		//If we are using droppables, inform the manager about the drop
		if ( $.ui.ddmanager && !this.options.dropBehaviour ) {
			$.ui.ddmanager.drop( this, event );
		}

		if ( this.options.revert ) {
			var that = this,
				cur = this.placeholder.offset(),
				axis = this.options.axis,
				animation = {};

			if ( !axis || axis === "x" ) {
				animation.left = cur.left - this.offset.parent.left - this.margins.left + ( this.offsetParent[ 0 ] === this.document[ 0 ].body ? 0 : this.offsetParent[ 0 ].scrollLeft );
			}
			if ( !axis || axis === "y" ) {
				animation.top = cur.top - this.offset.parent.top - this.margins.top + ( this.offsetParent[ 0 ] === this.document[ 0 ].body ? 0 : this.offsetParent[ 0 ].scrollTop );
			}
			this.reverting = true;
			$( this.helper ).animate( animation, parseInt( this.options.revert, 10 ) || 500, function() {
				that._clear( event );
			} );
		} else {
			this._clear( event, noPropagation );
		}

		return false;

	},

	cancel: function() {

		if ( this.dragging ) {

			this._mouseUp( { target: null } );

			if ( this.options.helper === "original" ) {
				this.currentItem.css( this._storedCSS );
				this._removeClass( this.currentItem, "ui-sortable-helper" );
			} else {
				this.currentItem.show();
			}

			//Post deactivating events to containers
			for ( var i = this.containers.length - 1; i >= 0; i-- ) {
				this.containers[ i ]._trigger( "deactivate", null, this._uiHash( this ) );
				if ( this.containers[ i ].containerCache.over ) {
					this.containers[ i ]._trigger( "out", null, this._uiHash( this ) );
					this.containers[ i ].containerCache.over = 0;
				}
			}

		}

		if ( this.placeholder ) {

			//$(this.placeholder[0]).remove(); would have been the jQuery way - unfortunately, it unbinds ALL events from the original node!
			if ( this.placeholder[ 0 ].parentNode ) {
				this.placeholder[ 0 ].parentNode.removeChild( this.placeholder[ 0 ] );
			}
			if ( this.options.helper !== "original" && this.helper && this.helper[ 0 ].parentNode ) {
				this.helper.remove();
			}

			$.extend( this, {
				helper: null,
				dragging: false,
				reverting: false,
				_noFinalSort: null
			} );

			if ( this.domPosition.prev ) {
				$( this.domPosition.prev ).after( this.currentItem );
			} else {
				$( this.domPosition.parent ).prepend( this.currentItem );
			}
		}

		return this;

	},

	serialize: function( o ) {

		var items = this._getItemsAsjQuery( o && o.connected ),
			str = [];
		o = o || {};

		$( items ).each( function() {
			var res = ( $( o.item || this ).attr( o.attribute || "id" ) || "" ).match( o.expression || ( /(.+)[\-=_](.+)/ ) );
			if ( res ) {
				str.push( ( o.key || res[ 1 ] + "[]" ) + "=" + ( o.key && o.expression ? res[ 1 ] : res[ 2 ] ) );
			}
		} );

		if ( !str.length && o.key ) {
			str.push( o.key + "=" );
		}

		return str.join( "&" );

	},

	toArray: function( o ) {

		var items = this._getItemsAsjQuery( o && o.connected ),
			ret = [];

		o = o || {};

		items.each( function() { ret.push( $( o.item || this ).attr( o.attribute || "id" ) || "" ); } );
		return ret;

	},

	/* Be careful with the following core functions */
	_intersectsWith: function( item ) {

		var x1 = this.positionAbs.left,
			x2 = x1 + this.helperProportions.width,
			y1 = this.positionAbs.top,
			y2 = y1 + this.helperProportions.height,
			l = item.left,
			r = l + item.width,
			t = item.top,
			b = t + item.height,
			dyClick = this.offset.click.top,
			dxClick = this.offset.click.left,
			isOverElementHeight = ( this.options.axis === "x" ) || ( ( y1 + dyClick ) > t && ( y1 + dyClick ) < b ),
			isOverElementWidth = ( this.options.axis === "y" ) || ( ( x1 + dxClick ) > l && ( x1 + dxClick ) < r ),
			isOverElement = isOverElementHeight && isOverElementWidth;

		if ( this.options.tolerance === "pointer" ||
			this.options.forcePointerForContainers ||
			( this.options.tolerance !== "pointer" && this.helperProportions[ this.floating ? "width" : "height" ] > item[ this.floating ? "width" : "height" ] )
		) {
			return isOverElement;
		} else {

			return ( l < x1 + ( this.helperProportions.width / 2 ) && // Right Half
				x2 - ( this.helperProportions.width / 2 ) < r && // Left Half
				t < y1 + ( this.helperProportions.height / 2 ) && // Bottom Half
				y2 - ( this.helperProportions.height / 2 ) < b ); // Top Half

		}
	},

	_intersectsWithPointer: function( item ) {

		var verticalDirection, horizontalDirection,
			isOverElementHeight = ( this.options.axis === "x" ) || this._isOverAxis( this.positionAbs.top + this.offset.click.top, item.top, item.height ),
			isOverElementWidth = ( this.options.axis === "y" ) || this._isOverAxis( this.positionAbs.left + this.offset.click.left, item.left, item.width ),
			isOverElement = isOverElementHeight && isOverElementWidth;

		if ( !isOverElement ) {
			return false;
		}

		verticalDirection = this._getDragVerticalDirection();
		horizontalDirection = this._getDragHorizontalDirection();

		return this.floating ?
			( ( horizontalDirection === "right" || verticalDirection === "down" ) ? 2 : 1 )
			: ( verticalDirection && ( verticalDirection === "down" ? 2 : 1 ) );

	},

	_intersectsWithSides: function( item ) {

		var isOverBottomHalf = this._isOverAxis( this.positionAbs.top + this.offset.click.top, item.top + ( item.height / 2 ), item.height ),
			isOverRightHalf = this._isOverAxis( this.positionAbs.left + this.offset.click.left, item.left + ( item.width / 2 ), item.width ),
			verticalDirection = this._getDragVerticalDirection(),
			horizontalDirection = this._getDragHorizontalDirection();

		if ( this.floating && horizontalDirection ) {
			return ( ( horizontalDirection === "right" && isOverRightHalf ) || ( horizontalDirection === "left" && !isOverRightHalf ) );
		} else {
			return verticalDirection && ( ( verticalDirection === "down" && isOverBottomHalf ) || ( verticalDirection === "up" && !isOverBottomHalf ) );
		}

	},

	_getDragVerticalDirection: function() {
		var delta = this.positionAbs.top - this.lastPositionAbs.top;
		return delta !== 0 && ( delta > 0 ? "down" : "up" );
	},

	_getDragHorizontalDirection: function() {
		var delta = this.positionAbs.left - this.lastPositionAbs.left;
		return delta !== 0 && ( delta > 0 ? "right" : "left" );
	},

	refresh: function( event ) {
		this._refreshItems( event );
		this._setHandleClassName();
		this.refreshPositions();
		return this;
	},

	_connectWith: function() {
		var options = this.options;
		return options.connectWith.constructor === String ? [ options.connectWith ] : options.connectWith;
	},

	_getItemsAsjQuery: function( connected ) {

		var i, j, cur, inst,
			items = [],
			queries = [],
			connectWith = this._connectWith();

		if ( connectWith && connected ) {
			for ( i = connectWith.length - 1; i >= 0; i-- ) {
				cur = $( connectWith[ i ], this.document[ 0 ] );
				for ( j = cur.length - 1; j >= 0; j-- ) {
					inst = $.data( cur[ j ], this.widgetFullName );
					if ( inst && inst !== this && !inst.options.disabled ) {
						queries.push( [ $.isFunction( inst.options.items ) ? inst.options.items.call( inst.element ) : $( inst.options.items, inst.element ).not( ".ui-sortable-helper" ).not( ".ui-sortable-placeholder" ), inst ] );
					}
				}
			}
		}

		queries.push( [ $.isFunction( this.options.items ) ? this.options.items.call( this.element, null, { options: this.options, item: this.currentItem } ) : $( this.options.items, this.element ).not( ".ui-sortable-helper" ).not( ".ui-sortable-placeholder" ), this ] );

		function addItems() {
			items.push( this );
		}
		for ( i = queries.length - 1; i >= 0; i-- ) {
			queries[ i ][ 0 ].each( addItems );
		}

		return $( items );

	},

	_removeCurrentsFromItems: function() {

		var list = this.currentItem.find( ":data(" + this.widgetName + "-item)" );

		this.items = $.grep( this.items, function( item ) {
			for ( var j = 0; j < list.length; j++ ) {
				if ( list[ j ] === item.item[ 0 ] ) {
					return false;
				}
			}
			return true;
		} );

	},

	_refreshItems: function( event ) {

		this.items = [];
		this.containers = [ this ];

		var i, j, cur, inst, targetData, _queries, item, queriesLength,
			items = this.items,
			queries = [ [ $.isFunction( this.options.items ) ? this.options.items.call( this.element[ 0 ], event, { item: this.currentItem } ) : $( this.options.items, this.element ), this ] ],
			connectWith = this._connectWith();

		if ( connectWith && this.ready ) { //Shouldn't be run the first time through due to massive slow-down
			for ( i = connectWith.length - 1; i >= 0; i-- ) {
				cur = $( connectWith[ i ], this.document[ 0 ] );
				for ( j = cur.length - 1; j >= 0; j-- ) {
					inst = $.data( cur[ j ], this.widgetFullName );
					if ( inst && inst !== this && !inst.options.disabled ) {
						queries.push( [ $.isFunction( inst.options.items ) ? inst.options.items.call( inst.element[ 0 ], event, { item: this.currentItem } ) : $( inst.options.items, inst.element ), inst ] );
						this.containers.push( inst );
					}
				}
			}
		}

		for ( i = queries.length - 1; i >= 0; i-- ) {
			targetData = queries[ i ][ 1 ];
			_queries = queries[ i ][ 0 ];

			for ( j = 0, queriesLength = _queries.length; j < queriesLength; j++ ) {
				item = $( _queries[ j ] );

				item.data( this.widgetName + "-item", targetData ); // Data for target checking (mouse manager)

				items.push( {
					item: item,
					instance: targetData,
					width: 0, height: 0,
					left: 0, top: 0
				} );
			}
		}

	},

	refreshPositions: function( fast ) {

		// Determine whether items are being displayed horizontally
		this.floating = this.items.length ?
			this.options.axis === "x" || this._isFloating( this.items[ 0 ].item ) :
			false;

		//This has to be redone because due to the item being moved out/into the offsetParent, the offsetParent's position will change
		if ( this.offsetParent && this.helper ) {
			this.offset.parent = this._getParentOffset();
		}

		var i, item, t, p;

		for ( i = this.items.length - 1; i >= 0; i-- ) {
			item = this.items[ i ];

			//We ignore calculating positions of all connected containers when we're not over them
			if ( item.instance !== this.currentContainer && this.currentContainer && item.item[ 0 ] !== this.currentItem[ 0 ] ) {
				continue;
			}

			t = this.options.toleranceElement ? $( this.options.toleranceElement, item.item ) : item.item;

			if ( !fast ) {
				item.width = t.outerWidth();
				item.height = t.outerHeight();
			}

			p = t.offset();
			item.left = p.left;
			item.top = p.top;
		}

		if ( this.options.custom && this.options.custom.refreshContainers ) {
			this.options.custom.refreshContainers.call( this );
		} else {
			for ( i = this.containers.length - 1; i >= 0; i-- ) {
				p = this.containers[ i ].element.offset();
				this.containers[ i ].containerCache.left = p.left;
				this.containers[ i ].containerCache.top = p.top;
				this.containers[ i ].containerCache.width = this.containers[ i ].element.outerWidth();
				this.containers[ i ].containerCache.height = this.containers[ i ].element.outerHeight();
			}
		}

		return this;
	},

	_createPlaceholder: function( that ) {
		that = that || this;
		var className,
			o = that.options;

		if ( !o.placeholder || o.placeholder.constructor === String ) {
			className = o.placeholder;
			o.placeholder = {
				element: function() {

					var nodeName = that.currentItem[ 0 ].nodeName.toLowerCase(),
						element = $( "<" + nodeName + ">", that.document[ 0 ] );

						that._addClass( element, "ui-sortable-placeholder",
								className || that.currentItem[ 0 ].className )
							._removeClass( element, "ui-sortable-helper" );

					if ( nodeName === "tbody" ) {
						that._createTrPlaceholder(
							that.currentItem.find( "tr" ).eq( 0 ),
							$( "<tr>", that.document[ 0 ] ).appendTo( element )
						);
					} else if ( nodeName === "tr" ) {
						that._createTrPlaceholder( that.currentItem, element );
					} else if ( nodeName === "img" ) {
						element.attr( "src", that.currentItem.attr( "src" ) );
					}

					if ( !className ) {
						element.css( "visibility", "hidden" );
					}

					return element;
				},
				update: function( container, p ) {

					// 1. If a className is set as 'placeholder option, we don't force sizes - the class is responsible for that
					// 2. The option 'forcePlaceholderSize can be enabled to force it even if a class name is specified
					if ( className && !o.forcePlaceholderSize ) {
						return;
					}

					//If the element doesn't have a actual height by itself (without styles coming from a stylesheet), it receives the inline height from the dragged item
					if ( !p.height() ) { p.height( that.currentItem.innerHeight() - parseInt( that.currentItem.css( "paddingTop" ) || 0, 10 ) - parseInt( that.currentItem.css( "paddingBottom" ) || 0, 10 ) ); }
					if ( !p.width() ) { p.width( that.currentItem.innerWidth() - parseInt( that.currentItem.css( "paddingLeft" ) || 0, 10 ) - parseInt( that.currentItem.css( "paddingRight" ) || 0, 10 ) ); }
				}
			};
		}

		//Create the placeholder
		that.placeholder = $( o.placeholder.element.call( that.element, that.currentItem ) );

		//Append it after the actual current item
		that.currentItem.after( that.placeholder );

		//Update the size of the placeholder (TODO: Logic to fuzzy, see line 316/317)
		o.placeholder.update( that, that.placeholder );

	},

	_createTrPlaceholder: function( sourceTr, targetTr ) {
		var that = this;

		sourceTr.children().each( function() {
			$( "<td>&#160;</td>", that.document[ 0 ] )
				.attr( "colspan", $( this ).attr( "colspan" ) || 1 )
				.appendTo( targetTr );
		} );
	},

	_contactContainers: function( event ) {
		var i, j, dist, itemWithLeastDistance, posProperty, sizeProperty, cur, nearBottom, floating, axis,
			innermostContainer = null,
			innermostIndex = null;

		// Get innermost container that intersects with item
		for ( i = this.containers.length - 1; i >= 0; i-- ) {

			// Never consider a container that's located within the item itself
			if ( $.contains( this.currentItem[ 0 ], this.containers[ i ].element[ 0 ] ) ) {
				continue;
			}

			if ( this._intersectsWith( this.containers[ i ].containerCache ) ) {

				// If we've already found a container and it's more "inner" than this, then continue
				if ( innermostContainer && $.contains( this.containers[ i ].element[ 0 ], innermostContainer.element[ 0 ] ) ) {
					continue;
				}

				innermostContainer = this.containers[ i ];
				innermostIndex = i;

			} else {

				// container doesn't intersect. trigger "out" event if necessary
				if ( this.containers[ i ].containerCache.over ) {
					this.containers[ i ]._trigger( "out", event, this._uiHash( this ) );
					this.containers[ i ].containerCache.over = 0;
				}
			}

		}

		// If no intersecting containers found, return
		if ( !innermostContainer ) {
			return;
		}

		// Move the item into the container if it's not there already
		if ( this.containers.length === 1 ) {
			if ( !this.containers[ innermostIndex ].containerCache.over ) {
				this.containers[ innermostIndex ]._trigger( "over", event, this._uiHash( this ) );
				this.containers[ innermostIndex ].containerCache.over = 1;
			}
		} else {

			//When entering a new container, we will find the item with the least distance and append our item near it
			dist = 10000;
			itemWithLeastDistance = null;
			floating = innermostContainer.floating || this._isFloating( this.currentItem );
			posProperty = floating ? "left" : "top";
			sizeProperty = floating ? "width" : "height";
			axis = floating ? "clientX" : "clientY";

			for ( j = this.items.length - 1; j >= 0; j-- ) {
				if ( !$.contains( this.containers[ innermostIndex ].element[ 0 ], this.items[ j ].item[ 0 ] ) ) {
					continue;
				}
				if ( this.items[ j ].item[ 0 ] === this.currentItem[ 0 ] ) {
					continue;
				}

				cur = this.items[ j ].item.offset()[ posProperty ];
				nearBottom = false;
				if ( event[ axis ] - cur > this.items[ j ][ sizeProperty ] / 2 ) {
					nearBottom = true;
				}

				if ( Math.abs( event[ axis ] - cur ) < dist ) {
					dist = Math.abs( event[ axis ] - cur );
					itemWithLeastDistance = this.items[ j ];
					this.direction = nearBottom ? "up" : "down";
				}
			}

			//Check if dropOnEmpty is enabled
			if ( !itemWithLeastDistance && !this.options.dropOnEmpty ) {
				return;
			}

			if ( this.currentContainer === this.containers[ innermostIndex ] ) {
				if ( !this.currentContainer.containerCache.over ) {
					this.containers[ innermostIndex ]._trigger( "over", event, this._uiHash() );
					this.currentContainer.containerCache.over = 1;
				}
				return;
			}

			itemWithLeastDistance ? this._rearrange( event, itemWithLeastDistance, null, true ) : this._rearrange( event, null, this.containers[ innermostIndex ].element, true );
			this._trigger( "change", event, this._uiHash() );
			this.containers[ innermostIndex ]._trigger( "change", event, this._uiHash( this ) );
			this.currentContainer = this.containers[ innermostIndex ];

			//Update the placeholder
			this.options.placeholder.update( this.currentContainer, this.placeholder );

			this.containers[ innermostIndex ]._trigger( "over", event, this._uiHash( this ) );
			this.containers[ innermostIndex ].containerCache.over = 1;
		}

	},

	_createHelper: function( event ) {

		var o = this.options,
			helper = $.isFunction( o.helper ) ? $( o.helper.apply( this.element[ 0 ], [ event, this.currentItem ] ) ) : ( o.helper === "clone" ? this.currentItem.clone() : this.currentItem );

		//Add the helper to the DOM if that didn't happen already
		if ( !helper.parents( "body" ).length ) {
			$( o.appendTo !== "parent" ? o.appendTo : this.currentItem[ 0 ].parentNode )[ 0 ].appendChild( helper[ 0 ] );
		}

		if ( helper[ 0 ] === this.currentItem[ 0 ] ) {
			this._storedCSS = { width: this.currentItem[ 0 ].style.width, height: this.currentItem[ 0 ].style.height, position: this.currentItem.css( "position" ), top: this.currentItem.css( "top" ), left: this.currentItem.css( "left" ) };
		}

		if ( !helper[ 0 ].style.width || o.forceHelperSize ) {
			helper.width( this.currentItem.width() );
		}
		if ( !helper[ 0 ].style.height || o.forceHelperSize ) {
			helper.height( this.currentItem.height() );
		}

		return helper;

	},

	_adjustOffsetFromHelper: function( obj ) {
		if ( typeof obj === "string" ) {
			obj = obj.split( " " );
		}
		if ( $.isArray( obj ) ) {
			obj = { left: +obj[ 0 ], top: +obj[ 1 ] || 0 };
		}
		if ( "left" in obj ) {
			this.offset.click.left = obj.left + this.margins.left;
		}
		if ( "right" in obj ) {
			this.offset.click.left = this.helperProportions.width - obj.right + this.margins.left;
		}
		if ( "top" in obj ) {
			this.offset.click.top = obj.top + this.margins.top;
		}
		if ( "bottom" in obj ) {
			this.offset.click.top = this.helperProportions.height - obj.bottom + this.margins.top;
		}
	},

	_getParentOffset: function() {

		//Get the offsetParent and cache its position
		this.offsetParent = this.helper.offsetParent();
		var po = this.offsetParent.offset();

		// This is a special case where we need to modify a offset calculated on start, since the following happened:
		// 1. The position of the helper is absolute, so it's position is calculated based on the next positioned parent
		// 2. The actual offset parent is a child of the scroll parent, and the scroll parent isn't the document, which means that
		//    the scroll is included in the initial calculation of the offset of the parent, and never recalculated upon drag
		if ( this.cssPosition === "absolute" && this.scrollParent[ 0 ] !== this.document[ 0 ] && $.contains( this.scrollParent[ 0 ], this.offsetParent[ 0 ] ) ) {
			po.left += this.scrollParent.scrollLeft();
			po.top += this.scrollParent.scrollTop();
		}

		// This needs to be actually done for all browsers, since pageX/pageY includes this information
		// with an ugly IE fix
		if ( this.offsetParent[ 0 ] === this.document[ 0 ].body || ( this.offsetParent[ 0 ].tagName && this.offsetParent[ 0 ].tagName.toLowerCase() === "html" && $.ui.ie ) ) {
			po = { top: 0, left: 0 };
		}

		return {
			top: po.top + ( parseInt( this.offsetParent.css( "borderTopWidth" ), 10 ) || 0 ),
			left: po.left + ( parseInt( this.offsetParent.css( "borderLeftWidth" ), 10 ) || 0 )
		};

	},

	_getRelativeOffset: function() {

		if ( this.cssPosition === "relative" ) {
			var p = this.currentItem.position();
			return {
				top: p.top - ( parseInt( this.helper.css( "top" ), 10 ) || 0 ) + this.scrollParent.scrollTop(),
				left: p.left - ( parseInt( this.helper.css( "left" ), 10 ) || 0 ) + this.scrollParent.scrollLeft()
			};
		} else {
			return { top: 0, left: 0 };
		}

	},

	_cacheMargins: function() {
		this.margins = {
			left: ( parseInt( this.currentItem.css( "marginLeft" ), 10 ) || 0 ),
			top: ( parseInt( this.currentItem.css( "marginTop" ), 10 ) || 0 )
		};
	},

	_cacheHelperProportions: function() {
		this.helperProportions = {
			width: this.helper.outerWidth(),
			height: this.helper.outerHeight()
		};
	},

	_setContainment: function() {

		var ce, co, over,
			o = this.options;
		if ( o.containment === "parent" ) {
			o.containment = this.helper[ 0 ].parentNode;
		}
		if ( o.containment === "document" || o.containment === "window" ) {
			this.containment = [
				0 - this.offset.relative.left - this.offset.parent.left,
				0 - this.offset.relative.top - this.offset.parent.top,
				o.containment === "document" ? this.document.width() : this.window.width() - this.helperProportions.width - this.margins.left,
				( o.containment === "document" ? this.document.width() : this.window.height() || this.document[ 0 ].body.parentNode.scrollHeight ) - this.helperProportions.height - this.margins.top
			];
		}

		if ( !( /^(document|window|parent)$/ ).test( o.containment ) ) {
			ce = $( o.containment )[ 0 ];
			co = $( o.containment ).offset();
			over = ( $( ce ).css( "overflow" ) !== "hidden" );

			this.containment = [
				co.left + ( parseInt( $( ce ).css( "borderLeftWidth" ), 10 ) || 0 ) + ( parseInt( $( ce ).css( "paddingLeft" ), 10 ) || 0 ) - this.margins.left,
				co.top + ( parseInt( $( ce ).css( "borderTopWidth" ), 10 ) || 0 ) + ( parseInt( $( ce ).css( "paddingTop" ), 10 ) || 0 ) - this.margins.top,
				co.left + ( over ? Math.max( ce.scrollWidth, ce.offsetWidth ) : ce.offsetWidth ) - ( parseInt( $( ce ).css( "borderLeftWidth" ), 10 ) || 0 ) - ( parseInt( $( ce ).css( "paddingRight" ), 10 ) || 0 ) - this.helperProportions.width - this.margins.left,
				co.top + ( over ? Math.max( ce.scrollHeight, ce.offsetHeight ) : ce.offsetHeight ) - ( parseInt( $( ce ).css( "borderTopWidth" ), 10 ) || 0 ) - ( parseInt( $( ce ).css( "paddingBottom" ), 10 ) || 0 ) - this.helperProportions.height - this.margins.top
			];
		}

	},

	_convertPositionTo: function( d, pos ) {

		if ( !pos ) {
			pos = this.position;
		}
		var mod = d === "absolute" ? 1 : -1,
			scroll = this.cssPosition === "absolute" && !( this.scrollParent[ 0 ] !== this.document[ 0 ] && $.contains( this.scrollParent[ 0 ], this.offsetParent[ 0 ] ) ) ? this.offsetParent : this.scrollParent,
			scrollIsRootNode = ( /(html|body)/i ).test( scroll[ 0 ].tagName );

		return {
			top: (
				pos.top	+																// The absolute mouse position
				this.offset.relative.top * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.top * mod -											// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) * mod )
			),
			left: (
				pos.left +																// The absolute mouse position
				this.offset.relative.left * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.left * mod	-										// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ) * mod )
			)
		};

	},

	_generatePosition: function( event ) {

		var top, left,
			o = this.options,
			pageX = event.pageX,
			pageY = event.pageY,
			scroll = this.cssPosition === "absolute" && !( this.scrollParent[ 0 ] !== this.document[ 0 ] && $.contains( this.scrollParent[ 0 ], this.offsetParent[ 0 ] ) ) ? this.offsetParent : this.scrollParent, scrollIsRootNode = ( /(html|body)/i ).test( scroll[ 0 ].tagName );

		// This is another very weird special case that only happens for relative elements:
		// 1. If the css position is relative
		// 2. and the scroll parent is the document or similar to the offset parent
		// we have to refresh the relative offset during the scroll so there are no jumps
		if ( this.cssPosition === "relative" && !( this.scrollParent[ 0 ] !== this.document[ 0 ] && this.scrollParent[ 0 ] !== this.offsetParent[ 0 ] ) ) {
			this.offset.relative = this._getRelativeOffset();
		}

		/*
		 * - Position constraining -
		 * Constrain the position to a mix of grid, containment.
		 */

		if ( this.originalPosition ) { //If we are not dragging yet, we won't check for options

			if ( this.containment ) {
				if ( event.pageX - this.offset.click.left < this.containment[ 0 ] ) {
					pageX = this.containment[ 0 ] + this.offset.click.left;
				}
				if ( event.pageY - this.offset.click.top < this.containment[ 1 ] ) {
					pageY = this.containment[ 1 ] + this.offset.click.top;
				}
				if ( event.pageX - this.offset.click.left > this.containment[ 2 ] ) {
					pageX = this.containment[ 2 ] + this.offset.click.left;
				}
				if ( event.pageY - this.offset.click.top > this.containment[ 3 ] ) {
					pageY = this.containment[ 3 ] + this.offset.click.top;
				}
			}

			if ( o.grid ) {
				top = this.originalPageY + Math.round( ( pageY - this.originalPageY ) / o.grid[ 1 ] ) * o.grid[ 1 ];
				pageY = this.containment ? ( ( top - this.offset.click.top >= this.containment[ 1 ] && top - this.offset.click.top <= this.containment[ 3 ] ) ? top : ( ( top - this.offset.click.top >= this.containment[ 1 ] ) ? top - o.grid[ 1 ] : top + o.grid[ 1 ] ) ) : top;

				left = this.originalPageX + Math.round( ( pageX - this.originalPageX ) / o.grid[ 0 ] ) * o.grid[ 0 ];
				pageX = this.containment ? ( ( left - this.offset.click.left >= this.containment[ 0 ] && left - this.offset.click.left <= this.containment[ 2 ] ) ? left : ( ( left - this.offset.click.left >= this.containment[ 0 ] ) ? left - o.grid[ 0 ] : left + o.grid[ 0 ] ) ) : left;
			}

		}

		return {
			top: (
				pageY -																// The absolute mouse position
				this.offset.click.top -													// Click offset (relative to the element)
				this.offset.relative.top	-											// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.top +												// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) )
			),
			left: (
				pageX -																// The absolute mouse position
				this.offset.click.left -												// Click offset (relative to the element)
				this.offset.relative.left	-											// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.left +												// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ) )
			)
		};

	},

	_rearrange: function( event, i, a, hardRefresh ) {

		a ? a[ 0 ].appendChild( this.placeholder[ 0 ] ) : i.item[ 0 ].parentNode.insertBefore( this.placeholder[ 0 ], ( this.direction === "down" ? i.item[ 0 ] : i.item[ 0 ].nextSibling ) );

		//Various things done here to improve the performance:
		// 1. we create a setTimeout, that calls refreshPositions
		// 2. on the instance, we have a counter variable, that get's higher after every append
		// 3. on the local scope, we copy the counter variable, and check in the timeout, if it's still the same
		// 4. this lets only the last addition to the timeout stack through
		this.counter = this.counter ? ++this.counter : 1;
		var counter = this.counter;

		this._delay( function() {
			if ( counter === this.counter ) {
				this.refreshPositions( !hardRefresh ); //Precompute after each DOM insertion, NOT on mousemove
			}
		} );

	},

	_clear: function( event, noPropagation ) {

		this.reverting = false;

		// We delay all events that have to be triggered to after the point where the placeholder has been removed and
		// everything else normalized again
		var i,
			delayedTriggers = [];

		// We first have to update the dom position of the actual currentItem
		// Note: don't do it if the current item is already removed (by a user), or it gets reappended (see #4088)
		if ( !this._noFinalSort && this.currentItem.parent().length ) {
			this.placeholder.before( this.currentItem );
		}
		this._noFinalSort = null;

		if ( this.helper[ 0 ] === this.currentItem[ 0 ] ) {
			for ( i in this._storedCSS ) {
				if ( this._storedCSS[ i ] === "auto" || this._storedCSS[ i ] === "static" ) {
					this._storedCSS[ i ] = "";
				}
			}
			this.currentItem.css( this._storedCSS );
			this._removeClass( this.currentItem, "ui-sortable-helper" );
		} else {
			this.currentItem.show();
		}

		if ( this.fromOutside && !noPropagation ) {
			delayedTriggers.push( function( event ) { this._trigger( "receive", event, this._uiHash( this.fromOutside ) ); } );
		}
		if ( ( this.fromOutside || this.domPosition.prev !== this.currentItem.prev().not( ".ui-sortable-helper" )[ 0 ] || this.domPosition.parent !== this.currentItem.parent()[ 0 ] ) && !noPropagation ) {
			delayedTriggers.push( function( event ) { this._trigger( "update", event, this._uiHash() ); } ); //Trigger update callback if the DOM position has changed
		}

		// Check if the items Container has Changed and trigger appropriate
		// events.
		if ( this !== this.currentContainer ) {
			if ( !noPropagation ) {
				delayedTriggers.push( function( event ) { this._trigger( "remove", event, this._uiHash() ); } );
				delayedTriggers.push( ( function( c ) { return function( event ) { c._trigger( "receive", event, this._uiHash( this ) ); };  } ).call( this, this.currentContainer ) );
				delayedTriggers.push( ( function( c ) { return function( event ) { c._trigger( "update", event, this._uiHash( this ) );  }; } ).call( this, this.currentContainer ) );
			}
		}

		//Post events to containers
		function delayEvent( type, instance, container ) {
			return function( event ) {
				container._trigger( type, event, instance._uiHash( instance ) );
			};
		}
		for ( i = this.containers.length - 1; i >= 0; i-- ) {
			if ( !noPropagation ) {
				delayedTriggers.push( delayEvent( "deactivate", this, this.containers[ i ] ) );
			}
			if ( this.containers[ i ].containerCache.over ) {
				delayedTriggers.push( delayEvent( "out", this, this.containers[ i ] ) );
				this.containers[ i ].containerCache.over = 0;
			}
		}

		//Do what was originally in plugins
		if ( this.storedCursor ) {
			this.document.find( "body" ).css( "cursor", this.storedCursor );
			this.storedStylesheet.remove();
		}
		if ( this._storedOpacity ) {
			this.helper.css( "opacity", this._storedOpacity );
		}
		if ( this._storedZIndex ) {
			this.helper.css( "zIndex", this._storedZIndex === "auto" ? "" : this._storedZIndex );
		}

		this.dragging = false;

		if ( !noPropagation ) {
			this._trigger( "beforeStop", event, this._uiHash() );
		}

		//$(this.placeholder[0]).remove(); would have been the jQuery way - unfortunately, it unbinds ALL events from the original node!
		this.placeholder[ 0 ].parentNode.removeChild( this.placeholder[ 0 ] );

		if ( !this.cancelHelperRemoval ) {
			if ( this.helper[ 0 ] !== this.currentItem[ 0 ] ) {
				this.helper.remove();
			}
			this.helper = null;
		}

		if ( !noPropagation ) {
			for ( i = 0; i < delayedTriggers.length; i++ ) {
				delayedTriggers[ i ].call( this, event );
			} //Trigger all delayed events
			this._trigger( "stop", event, this._uiHash() );
		}

		this.fromOutside = false;
		return !this.cancelHelperRemoval;

	},

	_trigger: function() {
		if ( $.Widget.prototype._trigger.apply( this, arguments ) === false ) {
			this.cancel();
		}
	},

	_uiHash: function( _inst ) {
		var inst = _inst || this;
		return {
			helper: inst.helper,
			placeholder: inst.placeholder || $( [] ),
			position: inst.position,
			originalPosition: inst.originalPosition,
			offset: inst.positionAbs,
			item: inst.currentItem,
			sender: _inst ? _inst.element : null
		};
	}

} );

} ) );