제이쿼리 validation 기능 잘 아시는 분 계신가요???

<script type="text/javascript">
jQuery(function($)
{
	$("#singupForm").validate({
		rules:{
			member_id:{
				required: true,
				minlength: 6,
				remote:{
					type:"post",
					url:"check_id.php"
					}
					},

		message:{
		member_id:{
		remote: $.validate.format("사용 가능합니다")
		},
		}
	});
	)};
	</script>

<?php
include $DOCUMENT_ROOT."/library/connect.php";
$valid = "true";
$request = trim(strtolower($_REQUEST['member_id']));

$result = mysql_query("SELECT * FROM member WHERE member_id = '$request'");

$num = mysql_num_rows($result);

if ($num > 0) {
$valid = "false";
}
echo $valid;
?>