<script language="JavaScript">
<!--
cal(0);

function cal(val){
	if (document.frm.quantity.value == "")
		document.frm.total_qty.value=val;
	else
		document.frm.total_qty.value=document.frm.quantity.value;	

	price=document.frm.quantity.value*document.frm.price.value;
	document.frm.product_costs.value=price;

	shipping_txt = document.frm.shipping.options[document.frm.shipping.selectedIndex].value
	if (shipping_txt == "" || shipping_txt == "self")
		shipping=0;
	else if (shipping_txt == "registered")
		shipping=0;//shipping=100;
	else if (shipping_txt == "express")
		shipping=0;//shipping=150;
	else if (shipping_txt == "messenger1")
		shipping=0;//shipping=200;
	else if (shipping_txt == "messenger2")
		shipping=0;//shipping=250;
	document.frm.ship_costs.value=shipping;

	document.frm.total_payment.value=shipping+price;	
}

function validate() {
	if (document.frm.quantity.value == "" || document.frm.quantity.value == "0") {
		alert("โปรดเลือกจำนวนสินค้า");
		return false;
	}
	if (document.frm.shipping.value == "") {
		alert("โปรดเลือกวิธีการส่งสินค้า");
		return false;
	}

	return true;
}

function validate2() {
	if (document.frm2.quantity.value == "" || document.frm2.quantity.value == "0") {
		alert("โปรดเลือกจำนวนสินค้า");
		return false;
	}	

	return true;
}
//-->
    </script>