title: onreadystatechange in AJAX not working
body: <p>I have a problem with the onreadystatechange when i make ajax request, it used to call the function but
  now it does not call the processRequest.</p>
  
  <p>I am not sure if I edited something or what..Can sombody help..</p>
  
  <pre><code>function createAjaxObject(url, callback) 
  {
      /// @par Implementation 
      var req = init();
    req.onreadystatechange = processRequest;
  
      /// @brief  Creates a ajax object based on the runnunf browser    
      function init() 
      {
          if (window.XMLHttpRequest)
              return new XMLHttpRequest();
          else if (window.ActiveXObject) 
              return new ActiveXObject("Microsoft.XMLHTTP");
      }
  
      /// @brief Checks if request is complete and HTTP call is successful
      function processRequest () 
      {   
  
          /// readyState of 4 signifies request is complete
  
          if (req.readyState == 4){
  
              /// status of 200 signifies sucessful HTTP call
              if (req.status == 200){
                  if (callback) 
                  callback(req.responseXML);
              }
          }
      }
  
       this.doPost = function(param) {
  
               if (req.readyState == 4) {
  
          /// make a HTTP GET request to the URL asynchronously
          req.open("POST",url, true);
          req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
          req.setRequestHeader("Content-length",param.length);
          req.setRequestHeader("Connection", "close");
          req.send(param);
  
          }
      }
  }
  </code></pre>
  
  <p>thanks,</p>