window.onload = function() {
	var mainNav = document.getElementById('mainMenuNav');
	var menuItems = mainNav.getElementsByTagName('li');
	for(i=0; i<menuItems.length; i++) {
		menuItems[i].onmouseover = function() {
			this.className = this.className + "Over";
		};
		menuItems[i].onmouseout = function() {
			this.className = this.className.replace("Over", "");
		};
	}
};