window.addEvent('domready', function(){ 
var totIncrement		= 0;
var increment			= 225;
var maxRightIncrement	= increment*(-6);
var fx = new Fx.Style('myList', 'margin-top', {
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);
}
}		  		  
})
});