jquery.tablednd.js

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    /** Get the position of an element by going up the DOM tree and adding up all the offsets */
    getPosition: function(e){
        var left = 0;
        var top  = 0;
        /** Safari fix -- thanks to Luis Chato for this! */
        if (e.offsetHeight == 0) {
            /** Safari 2 doesn't correctly grab the offsetTop of a table row
            this is detailed here:
            http://jacob.peargrove.com/blog/2006/technical/table-row-offsettop-bug-in-safari/
            the solution is likewise noted there, grab the offset of a table cell in the row - the firstChild.
            note that firefox will return a text node as a first child, so designing a more thorough
            solution may need to take that into account, for now this seems to work in firefox, safari, ie */
            e = e.firstChild; // a table cell
        }
		if (e && e.offsetParent) {
        	while (e.offsetParent){
            	left += e.offsetLeft;
            	top  += e.offsetTop;
            	e     = e.offsetParent;
        	}

        	left += e.offsetLeft;
        	top  += e.offsetTop;
        }

        return {x:left, y:top};
    },

    mousemove: function(ev) {
        if (jQuery.tableDnD.dragObject == null) {
            return;
        }

        var dragObj = jQuery(jQuery.tableDnD.dragObject);
        var config = jQuery.tableDnD.currentTable.tableDnDConfig;
        var mousePos = jQuery.tableDnD.mouseCoords(ev);
        var y = mousePos.y - jQuery.tableDnD.mouseOffset.y;
        //auto scroll the window
	    var yOffset = window.pageYOffset;
	 	if (document.all) {
	        // Windows version
	        //yOffset=document.body.scrollTop;
	        if (typeof document.compatMode != 'undefined' &&
	             document.compatMode != 'BackCompat') {
	           yOffset = document.documentElement.scrollTop;
	        }
	        else if (typeof document.body != 'undefined') {
	           yOffset=document.body.scrollTop;
	        }

	    }
		    
		if (mousePos.y-yOffset < config.scrollAmount) {
	    	window.scrollBy(0, -config.scrollAmount);
	    } else {
            var windowHeight = window.innerHeight ? window.innerHeight
                    : document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.clientHeight;
            if (windowHeight-(mousePos.y-yOffset) < config.scrollAmount) {
                window.scrollBy(0, config.scrollAmount);
            }
        }


        if (y != jQuery.tableDnD.oldY) {
            // work out if we're going up or down...
            var movingDown = y > jQuery.tableDnD.oldY;
            // update the old value
            jQuery.tableDnD.oldY = y;
            // update the style to show we're dragging
			if (config.onDragClass) {
				dragObj.addClass(config.onDragClass);
			} else {
	            dragObj.css(config.onDragStyle);
			}
            // If we're over a row then move the dragged row to there so that the user sees the
            // effect dynamically
            var currentRow = jQuery.tableDnD.findDropTargetRow(dragObj, y);
            if (currentRow) {
                // TODO worry about what happens when there are multiple TBODIES
                if (movingDown && jQuery.tableDnD.dragObject != currentRow) {
                    jQuery.tableDnD.dragObject.parentNode.insertBefore(jQuery.tableDnD.dragObject, currentRow.nextSibling);
                } else if (! movingDown && jQuery.tableDnD.dragObject != currentRow) {
                    jQuery.tableDnD.dragObject.parentNode.insertBefore(jQuery.tableDnD.dragObject, currentRow);
                }
            }
        }

        return false;
    },

    /** We're only worried about the y position really, because we can only move rows up and down */
    findDropTargetRow: function(draggedRow, y) {
        var rows = jQuery.tableDnD.currentTable.rows;
        for (var i=0; i<rows.length; i++) {
            var row = rows[i];
            var rowY    = this.getPosition(row).y;
            var rowHeight = parseInt(row.offsetHeight)/2;
            if (row.offsetHeight == 0) {
                rowY = this.getPosition(row.firstChild).y;
                rowHeight = parseInt(row.firstChild.offsetHeight)/2;
            }
            // Because we always have to insert before, we need to offset the height a bit
            if ((y > rowY - rowHeight) && (y < (rowY + rowHeight))) {
                // that's the row we're over
				// If it's the same as the current row, ignore it
				if (row == draggedRow) {return null;}
                var config = jQuery.tableDnD.currentTable.tableDnDConfig;
                if (config.onAllowDrop) {
                    if (config.onAllowDrop(draggedRow, row)) {
                        return row;
                    } else {
                        return null;
                    }
                } else {
					// If a row has nodrop class, then don't allow dropping (inspired by John Tarr and Famic)
                    var nodrop = jQuery(row).hasClass("nodrop");
                    if (! nodrop) {
                        return row;
                    } else {
                        return null;
                    }
                }
                return row;
            }
        }
        return null;
    },

    mouseup: function(e) {
        if (jQuery.tableDnD.currentTable && jQuery.tableDnD.dragObject) {
            var droppedRow = jQuery.tableDnD.dragObject;
            var config = jQuery.tableDnD.currentTable.tableDnDConfig;
            // If we have a dragObject, then we need to release it,
            // The row will already have been moved to the right place so we just reset stuff
			if (config.onDragClass) {
	            jQuery(droppedRow).removeClass(config.onDragClass);
			} else {
	            jQuery(droppedRow).css(config.onDropStyle);
			}
            jQuery.tableDnD.dragObject   = null;
            if (config.onDrop) {
                // Call the onDrop method if there is one
                config.onDrop(jQuery.tableDnD.currentTable, droppedRow);
            }
            jQuery.tableDnD.currentTable = null; // let go of the table too
        }
    },

    serialize: function() {
        if (jQuery.tableDnD.currentTable) {
            return jQuery.tableDnD.serializeTable(jQuery.tableDnD.currentTable);
        } else {
            return "Error: No Table id set, you need to set an id on your table and every row";
        }
    },

	serializeTable: function(table) {
        var result = "";
        var tableId = table.id;
        var rows = table.rows;
        for (var i=0; i<rows.length; i++) {
            if (result.length > 0) result += "&";
            var rowId = rows[i].id;
            if (rowId && rowId && table.tableDnDConfig && table.tableDnDConfig.serializeRegexp) {
                rowId = rowId.match(table.tableDnDConfig.serializeRegexp)[0];
            }

            result += tableId + '[]=' + rowId;
        }
        return result;
	},

	serializeTables: function() {
        var result = "";
        this.each(function() {
			// this is now bound to each matching table
			result += jQuery.tableDnD.serializeTable(this);
		});
        return result;
    }

}

jQuery.fn.extend(
	{
		tableDnD : jQuery.tableDnD.build,
		tableDnDUpdate : jQuery.tableDnD.updateTables,
		tableDnDSerialize: jQuery.tableDnD.serializeTables
	}
);