var slideMe = new Class({
	initialize: function(mask){
		this.mask = mask.addEvents({
			mouseenter: this.stop.bind(this),
			mouseleave: this.play.bind(this)
		});
		this.el = this.mask.getFirst();
		this.elSize = this.el.offsetHeight;
		this.maskSize = this.mask.offsetHeight;
		this._mover = false;
		this.play();

		return this;
	},

	mover: function(){
		var current = this.el.getStyle('top').toInt();
		if(current<-this.elSize){
			current = this.maskSize;
		}
		this.el.setStyle('top',(current-1)+'px');
	},

	play: function(){
		this._mover = this.mover.periodical(40,this);
	},

	stop: function(){
		$clear(this._mover);
	}
});

window.addEvent('domready',function(){
	var slide1 = new slideMe($('mask1'));
	var slide2 = new slideMe($('mask2'));
});