buttons = function() {
	buttons = document.getElementById('navigation').getElementsByTagName('li');
	for (var i=0; i<buttons.length; i++) {
		buttons[i].onmouseover=function() {
			this.className+="x_hover";
		}
		buttons[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp("x_hover\\b"), "");
		}
	}
}

if (window.attachEvent) window.attachEvent("onload", buttons);