window.addEvent('domready', function(){
	var totIncrement = 0;
	var increment = 220;
	var number = document.getElementById("slider").getAttribute('number');
	var maxRightIncrement = increment*(-number+4);
	var fx = new Fx.Style('slider', 'margin-left',{
			duration: 1000,
			transition: Fx.Transitions.Back.easeInOut,
			wait: true
	});
//-------------------------------------
// EVENTS for the button "previous"
	$('previous').addEvents({
		'click' : function(event){
		if(totIncrement<0){
				totIncrement = totIncrement+increment;
				fx.stop()
				fx.start(totIncrement);
			}
		}
	}); 
 
//-------------------------------------
// EVENTS for the button "next"
	$('next').addEvents({ 
			'click' : function(event){ 
			if(totIncrement>maxRightIncrement){
				totIncrement = totIncrement-increment;
				fx.stop()
				fx.start(totIncrement);
				if(totIncrement==maxRightIncrement);
			}
		}
	});

});