Using AJAX for getting data on web pages without reloading them ?

We have to be a bit familiar with the Java script for the use of ajax.

In this example ,a java script function which is calling the post function using ajax.

<script type="type/javascript" >

function ajaxunload()

{
//here we created the obj of the xmlhttprequest , which is a mile stone to ajax .
//all latest browser like internet explorer 5 or abve uses activeXobject
//this object exchanges the data with the server ..

obj  = new XMLHttpRequest();

//It stores the function or the name of the function to be called automatically when the readystate //property changes 

 obj.onreadystatechange = function ()

 {

   if (obj.readyState == 4 && obj.status == 200)
{
// here we are storing the data which is returend from the ajax function.
  var s = obj.responseText
   obj.abort();

  }

 }

  obj.open("POST", "postfunction", true);

  obj.send();

}

</script>