AJAX function to retrieve content from the server

function getContent(page, params, elementid, waitmsg){
//params has to have following format
//i.e.: c=1&id=3....
//page is the server side script. include full path
//i.e. ../scripts/myscript.php

//Clear our fetching variable
var xmlhttp=false;
//Try to create active x object
try {
    xmlhttp = new ActiveXObject('Msxml2.XMLHTTP'); 
    } catch (e) {
    try {
         xmlhttp = new ActiveXObject('Microsoft.XMLHTTP'); 
    } catch (E) {
         xmlhttp = false;
    }
 }
 if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
     xmlhttp = new XMLHttpRequest();
 }

//This is the path to the PHP file on the server
var file = page+params;

//Open the file through GET, and add the page we want to retrieve as a GET variable
xmlhttp.open('GET', file, true);    

xmlhttp.onreadystatechange=function() {
if(xmlhttp.readyState == 1){
 
//Display waiting image and message while content loads.
//Make sure you have the corect path for the image
document.getElementById(elementid).innerHTML = "<p><img src='images/waiting.gif' align='middle'> Please wait... <br />"+waitmsg+ "</p>" ;

   //Check if it is ready to recieve data 
   }else if(xmlhttp.readyState==4) { 
   //Make sure there is something in the content variable
   var content = xmlhttp.responseText;

      //The content data which has been retrieved
      if( content ){   
      //Change the inner content of your div to the newly retrieved content
      document.getElementById(elementid).innerHTML = content;   
      }
   }
}
//Nullify the XMLHttpRequest
xmlhttp.send(null)
return;
}