function check_track_order(f) {
	if(f.order_item.value==''){
		alert('Please input Order/Item ID.');
		f.order_item.focus();
		return false;
	}
	if(f.order_item.value.length != '8' && f.order_item.value.length != '12'){
		alert('Wrong Order/Item ID.');
		f.order_item.focus();
		return false;
	}
	if(f.email.value == ''){
		alert('Please input the Payment Email Address.');
		f.email.focus();
		return false;
	}
	if(!chkMail(f.email)){
		alert('Wrong Email Address!');
		f.email.focus();
		return false;
	}
	return true;
}

function chkMail(e){
	var email = e.value;
	var pattern = /^([a-zA-Z0-9_'.-])+@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-])+/;
	chkFlag = pattern.test(email);
	if(chkFlag){
		return true;
	}else{
		return false;
	}
}