prepareDropDown = function() {
	var listItems = document.getElementById("menu").getElementsByTagName("LI");
	for (var i=0; i<listItems.length; i++) {
		listItems[i].onmouseover = function() {
			this.className += "hover";
		}
		listItems[i].onmouseout = function() {
			this.className = this.className.replace(new RegExp("hover\\b"), "");
		}
	}
}
window.onload = prepareDropDown;