jQuery Validation and default messages

Here is how we specify errors messages for the jQuery Validation plugin by Jörn Zaefferer: For built-in validators we modify $.validator.messages, as Jörn shows here.

$.extend($.validator.messages, {
  required: "Required",
  email: "Email not valid",
  ...
});

(we fill the actual messages in server-side processing, we don't hard-code them in the JS) For custom validators we... add custom validators.

$.validator.addMethod(
  "shouldBeGreen",
  function(value, element) {
    return this.optional(element) || /green/.test(value);
  },
  "Not green"
);

Now we can specify 'shouldBeGreen' in an input's class. That's it. Pretty simple, but it took us a while to figure it out so I hope this helps somebody.