function getObjById(id) {
	if (document.getElementById) {
		return document.getElementById(id);
	}
	if(document.all){ 
		return document.all[id];
	}
	if (document.layers) {
		return document.layers[id];
	}
}

function calcPrice()
{
	pyform = document.forms['frm_orderInfo'];

	quantity = pyform.elements['quantity'].value;
	if ((!(/^\d+$/.test(quantity))) || quantity==0)	//用正则表达式判断quantity不是正整数。
	{
		if (quantity!='')	//如果quantity不为空
			pyform.elements['quantity'].value=1
		quantity=1
	}

	price = pyform.elements['price'].value;

	var total = price*quantity;
	getObjById('totalcost').innerHTML=total.toFixed(2);
	pyform.elements['total_fee'].value=total.toFixed(2);

	return total;
}