if (typeof addLoadEvent != 'function') {
	function addLoadEvent(func) {
	  var oldonload = window.onload;
	  if (typeof window.onload != 'function') {
		window.onload = func;
	  } else {
		window.onload = function() {
		  if (oldonload) {
		    oldonload();
		  }
		  func();
		}
	  }
	}
}
	
addLoadEvent(dropdownMenu);

function dropdownMenu() {
	var ulArray = document.getElementsByTagName('ul');
	var targetUl;
	
	for (var index = 0 ; index < ulArray.length ; index++) {
		targetUl = ulArray[index];
		if (targetUl.className.search('children') >= 0) {
			targetUl.parentNode.onmouseover = showChildrenUl;
			targetUl.parentNode.onmouseout = hideChildrenUl;
		}
	}
}

function showChildrenUl() {
	var childNodeArray = this.childNodes;
	
	for (var index = 0 ; index < childNodeArray.length ; index++) {
		targetUl = childNodeArray[index];
		if (targetUl.tagName == 'UL') {
			targetUl.style.display = 'block';
		}
	}
}

function hideChildrenUl() {
	var childNodeArray = this.childNodes;
	
	for (var index = 0 ; index < childNodeArray.length ; index++) {
		targetUl = childNodeArray[index];
		if (targetUl.tagName == 'UL') {
			targetUl.style.display = 'none';
		}
	}
}