window.addEvent('domready', function(){ 
      var totIncrement      = 0;
      var increment         = 500;
      var maxRightIncrement = increment*(-8);
      var fx = new Fx.Style('wide-container', 'margin-left', {
                duration: 750,
                transition: Fx.Transitions.Sine.easeInOut,
                wait: true
       });

      $('previous').addEvents({ 
          'click' : function(event){ 
          if(totIncrement<0){
                    totIncrement = totIncrement+increment;
                    fx.stop()
                    fx.start(totIncrement);
                }
            }                 
      }); 
     
      $('next').addEvents({ 
          'click' : function(event){ 
             if(totIncrement>maxRightIncrement){
                 totIncrement = totIncrement-increment;
                fx.stop()
                fx.start(totIncrement);
            }
          }               
      })

     
});