function check_amount_shoppingcart(){
	var error = '';
	
	dojo.query('INPUT[name^=cart_quantity]').forEach(function(node){
		var quantity_available = parseInt(dojo.attr(node, "quantity_available"));
		var product_name = dojo.attr(node, "product_name");
		if(node.value > quantity_available)
			error += "product \"" + product_name + "\" maximum available " + quantity_available + "\n";
	});
	
	if(error){
		error = "We apologize, but you are not able to order this amount of product:\n---------------------------------\n" + error + "---------------------------------";
		alert(error);
		return false;
	}else return true;
}