function over() {
	var navItems = document.getElementById("nav").getElementsByTagName("li");
	for (var i=0; i<navItems.length; i++) {
		navItems[i].onmouseover=function() { this.className += "over"; }
		navItems[i].onmouseout=function() { this.className = ""; }
	}
}
window.onload = over;