SharePoint Designer Validation Regular Expression

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script>
<script type="text/javascript" src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.min.js"></script>

<script type="text/javascript">

$(document).ready(function() {

$("#aspnetForm").validate({
submitHandler: function(form) {
}});

$.validator.addMethod(
     "regex",
     function(value, element, regexp) {
         var check = false;
         var re = new RegExp(regexp);
         return this.optional(element) || re.test(value);
     },""
);

// VALIDATE TITLE
$("input[title='Title']").rules("add",{
required: true,
regex:"^([_a-zA-Z0-9-]+)(\.[_a-zA-Z0-9-]+)*@([a-zA-Z0-9-]+\.)+([a-zA-Z]{2,3})$",
messages: {
regex: "<br />Enter valid email address."
}
});

// BLUR -  Set focus after alert
$("input[title='Title']").blur(function() {
if (!$("input[title='Title']").valid()) {
this.focus();
}
});

// SAVE - Cannot save if regex rules adds
$("input[value='Save']").focus(function(){
if (!$("input[title='Title']").valid()) {
alert("You cannot save this Item..");
$("input[title='Title']").focus();
}
});

});

</script>