I'm trying to check whether a URL is from the same domain with jQuery Validation addMethod.

Here's what i got so far, but it doesn't seem to be working:

jQuery.validator.addMethod("domain", function(value, element) { 
            return this.optional(element) || /^http:\/\/testsite.com/.test(value); 
        }, "The URL doesn't match.");

        $("#url_form").validate({
          rules: {
            url: {
              required: true,
              url: true,
              domain : true 
            }
          }
        });