[SOLVED] Ajax POST issues

[HomerTheDragoon]

This is my function that is suppose to send the data over to the php script. However I can not get a read out of any kind. I have my php script just echo something to ensure it is running the script and I have it alert for the callback. But it doesn't seem to be getting that far. I'm new to ajax, and really new to POST ajax. I can get my GET's working fine. please help.

function postComment(url,pid,category,content)
{
var params = "content=" + content + "&pid="+pid+"&category="+category;
var xmlHttp;
try
  {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest();
  }
catch (e)
  {
  // Internet Explorer
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    try
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    catch (e)
      {
      alert("Your browser does not support AJAX!");
      return false;
      }
    }
  }
xmlHttp.onreadystatechange=function()
    {
    if(xmlHttp.readyState==4)
      {
      alert(xmlHttp.responseText);
      }
      }
  xmlHttp.open("POST",url,true);
  http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.setRequestHeader("Content-length", params.length);
http.setRequestHeader("Connection", "close");
  http.send(params);
  }

[HomerTheDragoon]

Edit Figured it out.