function  initZoom()
{
   $$('.jsPetitZoom').each(function(obj)
           {
               var id = obj.id.split('_');
               id = id[1];

               Event.observe(obj, 'mouseover', function(event) {
                   $('zoom_'+id).show();
                   $('jsImage_'+id).hide();
               });

                 Event.observe(obj, 'mouseout', function(event) {
                   $('zoom_'+id).hide();
                   $('jsImage_'+id).show();
               });
   });
}

Event.observe(window, 'load', function() {
   initZoom();
});