Is it possible to call ASP.NET codebehind function from JavaScript.
I would prefer Muhammad Akhtar PageMethod approach. Just one short note: You don't need the scriptmanager. The scriptmanager only generates the javascript proxy methods for you. If you already have JQuery on your page, you can forget about the scriptmanager and write something like this on your page instead:
this assumes that you have a link with the ID AjaxLink on your page as well as a div with the id content that shows the result. The benefit is that you save 30kb javascript compared between jquery and the injected scripts by the scriptmanager