How the use Ajax with Codeigniter?

[eluser]skunkbad[/eluser]
[quote author="ytsejam" date="1344075129"]How can i enable the ajax? ...[/quote]

Ajax is part of javascript. I use jQuery to handle ajax because even after using javascript for years, I still feel like an imbecile. You will normally want to use ajax to do a POST request, where the post data is validated and used to generate content that is passed back to the browser. That response can be in a few forms, and the most common is JSON. If you have any javascript already, you will probably need to show it so we know what you are doing client-side, or your chances of getting help are slim to none.