function Go(location, prod_id2, cat_id) {	
	if (document.all)
	   key = document.getElementById("selcompara").value;	
	else
	   var key = document.comp1.selcompara.options[document.comp1.selcompara.selectedIndex].value;

	var ref = location + '/index.php?option=com_phpshop&page=shop.product_compare&category_id=' + cat_id +'&product_id=' + key + '&product_id2='+prod_id2;		
	document.location.href = ref;
} 

function Go2(location, prod_id, cat_id) {	
	if (document.all)
	   key = document.getElementById("selcompara2").value;	
	else
	   var key = document.comp2.selcompara2.options[document.comp2.selcompara2.selectedIndex].value;

	var ref = location + '/index.php?option=com_phpshop&page=shop.product_compare&category_id=' + cat_id+'&product_id2=' + key + '&product_id='+prod_id;	
	document.location.href = ref;
}