mysql - Implement validation using ajax along with php -

I am creating a website using php + mysql. I have a registration page and have already implemented it in php has gone. Now I would like to make the page more dynamic and interactive than using AJAX. I would like a feature in which the user goes to the next tab, it should display the message in the previous field by right / wrong on the basis of user's data. Can anyone tell me that it is possible to add this feature to a PHP page or should I start from scratch? Please tell me if there is a good source for learning AJAX

Check it out: A very important thing to know about Ajax, or you can jump straight on, is to remember that if you have a Validate the fields using, even when processed on the form On the go, you should always verify and verify on the server, because web request can be easily fake.