function nav(){
	var easingMethod = 'Sine'; // Quad , Cubic , Quart, Quint , Pow, Expo, Circ, Sine, Back, Bounce, Elastic
	var easing = 'easeInOut'; //easeIn , easeOut, easeInOut
	var nav = $('nav');
	var _el = nav.getChildren('li');
	var moover = new Element('li',{'class':'back'});

	var moover_x = moover;

	moover.innerHTML = '<div class="left"></div>';
	moover.injectInside(nav);

	var active;
	var _t = null;
	_el.each(function(obj){
		if(obj.getElements('a')[0].hasClass('active')) active=obj;
	});
	if(!active) active=_el[0];
	moover.setStyles({
		left: active.offsetLeft+'px',
		width: active.offsetWidth+'px'
	});
	var slide = new Fx.Styles( moover, {duration: 500, transition: Fx.Transitions[easingMethod][easing], link: 'cancel'});
	_el.addEvent('mouseenter', function(){
		var _this = this;
		slide.stop();
		slide.start({
			'left': _this.offsetLeft,
			'width': _this.offsetWidth
		});
	});

	var _timer;
	nav.addEvent('mouseleave', function(){
		slide.stop();
		slide.start({
			'left': active.offsetLeft,
			'width': active.offsetWidth
		});
	});
}

window.addEvent('domready', function(){
	nav();
});