Make a basic CallBack functionality (using XmlHttp object)

Hi,
It's so easy to implement a basic call back functionality (in asynchronous xmlhttp method) and to use it in your web pages(One of the Ajax implementation).
You just need to use XmlHttp object and to wrap the code with some java script function.

For example:
Code for client side:

And for server side:

And that's all, you have a basic CallBack functionality!