JQuery Username Validation
问题 I'm new to JQuery and attempting to write a script to check username availability. My problem is that no matter what I type, I always get back "This username is already in use." JQuery source: $(document).ready(function() { jQuery.validator.addMethod("usernameCheck", function(username) { var isSuccess = false; $.ajax({ url: "username_availability.php", data: "username=" + username, async: false, success: function(msg) { isSuccess = msg === "TRUE" ? true : false } }); return isSuccess; },"");