function load_events() { enable_submit(); }
function enable_submit() { document.getElementById("invio").disabled = false; }
function disable_submit() { document.getElementById("invio").disabled = true; }

function goToProducts(product_id, visit_date)
{
    if (product_id != 0) {
	    window.location.href = "/shop/product.php?productid=" + product_id + "&visit_date=" + visit_date;
    }
}