addLoadEvent(dropdownNav);

function dropdownNav(){
	var navRoot = document.getElementById('leftnav');
	if (!navRoot){
		return;
	}
	var li_list = navRoot.getElementsByTagName('li');
	for (var i=0; i<li_list.length; i++){
			li_list[i].onmouseover = function(){
				this.className = 'parent_on';
				for (var n=0; n<this.childNodes.length; n++){
					var ul_node = this.childNodes[n];
					if (ul_node.nodeName == 'UL'){
						this.childNodes[n].className += ' on';

					}
				}
			}
			li_list[i].onmouseout = function(){
				this.className = 'parent_off';
				for (var n=0; n<this.childNodes.length; n++){
					var ul_node = this.childNodes[n];
					if (ul_node.nodeName == 'UL'){
						this.childNodes[n].className = '';

					}
				}
			}
	}

}