Im trying to implement this and Im not sure if there is a syntax difference in returning a value of a checkbox vs a dropdown menu. Is (return $("#referrer").val() == 'Other') the proper way to test the value of a checkbox? It certainly works for dropdown menus..
Here is my new code, mimicking the syntax of the example you provided: $("#signupForm").validate({ rules: { referrer: { required: true, minlength: 1 }, referrerother: { required: function(element){ return $("#referrer").val() == 'Other' }, minlength: 1 } }, messages: { referrerother: "If you select 'other', you must enter it." } }); Here is my updated code: http://psylicyde.com/misc/jquery-validate/demo/test.html