function tree_toggle(event){event=event||window.event;var clickedElem=event.target||event.srcElement;if(!hasClass(clickedElem,'Expand')){return;}var node=clickedElem.parentNode;if(hasClass(node,'ExpandLeaf')){return;}var newClass=hasClass(node,'ExpandOpen')?'ExpandClosed':'ExpandOpen';var re=/(^|\s)(ExpandOpen|ExpandClosed)(\s|$)/;node.className=node.className.replace(re,'$1'+newClass+'$3');}function hasClass(elem,className){return new RegExp("(^|\\s)"+className+"(\\s|$)").test(elem.className);}