function list_product()
{
var brand_id = 0;
var type_id = 0;

var brand_id = document.getElementById("printer_make_id").value;
var type_id = document.getElementById("printer_family_id").value;
if(brand_id!=0 && type_id!=0) {
window.location="index.php?chmod=true&b_id="+brand_id+"&t_id="+type_id;
}

}