How to validate form attributes respectively and instantly via ajax?

Hi All!

I want to check if a username or an email is available when users register an account.

Now the php code like this can do with a form submitted entirely:

$form = new RegistrationForm;

$form->attributes = $_POST['RegistrationForm'];//array('username'=>'aaaa','password'=>'bbbb','email'=>'')





//list all error messages


How can I validate only one attribute at a time?

Thank you in advance.

How do you want to validate?

$form = new RegistrationForm;

$form->attributes = $_POST[‘RegistrationForm’];//array(‘username’=>‘aaaa’,‘password’=>‘bbbb’,‘email’=>‘’)

You may try:

//This validates only the username

if ($form->validate(array(‘username’))) {


This is for validating a single attribute.