var menuvelocity = 1000; // px/s
var menulastobj = null;
var menucurrentobj = null;
function menuinit(obj) {
	menucurrentobj = obj;
	$('menuslider').setStyles({
		left: obj.parentNode.offsetLeft,
		display: ''
	});
}
function menuslide(obj) {
	if (!menucurrentobj || menulastobj == obj) return;
	var slider = $('menuslider');
	var dist = Math.abs(slider.getStyle('left').toInt()-obj.parentNode.offsetLeft);
	slider.get('tween',{
		duration: dist/menuvelocity*1000,
		transition: 'quad:in:out'
	}).start('left',obj.parentNode.offsetLeft);
	menulastobj = obj;
}