Hi everyone

I'm a complete and utter AJAX noob and have been sitting with the same problem for the last 3 hours. I'm trying to display a dynamically generated calendar (generated via PHP using a database). But before I continue, here's my javascript...

Code:
function loadURL(url){
  var params = "year=2007&month=8";
  
  try {
    xmlhttp = window.XMLHttpRequest?new XMLHttpRequest(): new ActiveXObject("Microsoft.XMLHTTP");
  } 
  catch (e) {
    alert(e);
  }
  
  xmlhttp.onreadystatechange = function(){
    if ((xmlhttp.readyState == 4) && (xmlhttp.status == 200)) {
      // xmlhttp.responseText object contains the response.
      document.getElementById("calDiv").innerHTML = xmlhttp.responseText;
    }
    else{
      document.getElementById("calDiv").innerHTML = "LOADING";
    }   
  };
  
  xmlhttp.open('POST', url); 
  xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  xmlhttp.send(params); 

}
The calendar does display when the loadURL function is called, but doesn't display using the paramaters defined in the "params" variable, it defaults to the current month (that's part of my php script, so it's supposed to do that). So, it seems to me that xmlhttp.send(params) isn't actually sending the desired paramaters.

Can anyone please help me with this, as I am running short on hair. Thanks