get values on server-side sent with xmlHttp.open ajax/javascript [duplicate]

Possible Duplicate:
get values on server-side sent with xmlHttp.open(GET
Get value from AJAX using Javascript and ASP

I have two values ( numbers ) on the client side ASP javascript that I want to send to the server-side asp javascript. so my code is this: ( client side )

function receiveResult(_data,nbquestions)
   {
//alert(nbquestions)
//alert(_data)  


     var xmlHttp;
        try

     {
    /* Firefox, opera */
    xmlHttp=new XMLHttpRequest();
  }
  catch (e)
  {
    /* IE 9 */
    try
    {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e)
    {
      /* IE 6.x-8*/
      try
      {
        xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (e)
      {
        alert("Your browser is old please update it !");
        return false ;
      }
    }
  }
  xmlHttp.onreadystatechange=function()
  {
    if(xmlHttp.readyState==4)
    {
      /* this puts the value into an alert */



    }
  }
  // send querystring to the server-side 
  xmlHttp.open("post","CmsAjax.asp",true)
  xmlHttp.send("param1="+_data+"&param2="+nbquestions);
}

I have two questions:

1. Is the xmlHttp.send correctly written?

2. How do I get the values on the server-side using JavaScript?