function validChars(e, goods) {
	
	var key, keychar;
	key = (window.event) ? window.event.keyCode : ((e) ? e.which : null);
	if (key == null) return true;
 
	keychar = String.fromCharCode(key);
	keychar = keychar.toLowerCase();
	goods = goods.toLowerCase();
 
	if (goods.indexOf(keychar) != -1)
		return true;
 
	if (key==null || key==0 || key==8 || key==9 || key==13 || key==27)
		return true;
 
	return false;
}

function AmountCount(id){
	
	var price = document.getElementById("amount_hidden_" + id).value;
	var num = document.getElementById("inputnum_" + id).value;
	
	document.getElementById("this_amount_" + id).innerHTML = price*num;	
	document.getElementById("total_amount").innerHTML = 0;
	
	for(i=1; i<=id; i++){
		
		document.getElementById("total_amount").innerHTML = parseFloat(document.getElementById("total_amount").innerHTML) + parseFloat(document.getElementById("this_amount_" + id).innerHTML);
	}
}