I am getting stuck up.
i am using ajax concept in my application.
i used req.open("POST",url,true) method
i am trying to post values to the action class.
i.e. i am sending parameters through req.send(params).This is working perfectly in IE.
But it is not working in mozilla firefox.
the values send are becoming null.
please send me the reply.

Try setting header before sending request :

req.open('POST', url, true);
req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
req.setRequestHeader("Content-length", params.length);
req.setRequestHeader("Connection", "close");
req.send(params);

i used the ajax code to open the html form direcly. it is working fine with the IE but not showing the form content with the mozilla firefox.
sample code:
file1.php

function ListIncevOfUser(){

var request = createRequestObject();
var param="";


param+="&memid="+memid;
param+="&level="+level;

document.getElementById('incen').innerHTML = '';
/* Opening a request */
request.open("POST", "file2.php",true);
request.setRequestHeader('Content-Type','application/x-www-form-urlencoded');

request.onreadystatechange = function()
{
if(request.readyState == 4)
{
response = request.responseText;


document.getElementById('incen').innerHTML = response;


}
};

request.send(param);

}