使用jquery / ajax进行Zend Server端验证

I wish to run few server side methods for validation and returning content/messages on the main page/view. But no luck so far. All I could find was running JS based validation scripts. For the start, I am looking to validate my login/registration form using ajax and server side methods. Just want to see if the user is already registered, he entered valid information..and all through php code..not JS code..any ideas?I wish to run few server side methods for valid