function checkBeforeComparison()
{var id_list='';$('.comparator:checked').each(function()
{id_list+=$(this).val()+'|';});$('.compare_product_list').val(id_list);if($('.comparator:checked').length==0)
{alert(min_item);return false;}
return true;}
function checkForComparison(nb_max_item)
{if($('.comparator:checked').length>nb_max_item)
alert(max_item);}