Need help with AJAX

programming web dev
1

I’m trying to implement some AJAX on my server but I get in some kind of a jam and would like your opinion on it.

Here’s the code


// holds an instance of XMLHttpRequest
var xmlHttp = createXmlHttpRequestObject();
// holds the remote server address and parameters
var serverAddress = "scripts/directory.php?";
// variables that establish how often to access the server
var updateInterval = 5; // how many seconds to wait to get new message
var errorRetryInterval = 30;
// when set to true, display detailed error messages
var debugMode = true;
// creates and XMLHttpRequest instance
function createXmlHttpRequestObject()
{
  // will store the reference to the XmlHttpRequest object
  var xmlHttp;
  // this should work for all browsers except IE6 and older
  try
  {
    // try to create XmlHttpRequest object
    xmlHttp = new XMLHttpRequest();
  }
  catch(e)
  {
    // assume IE6 or older
    var XmlHttpVersions = new Array("MSXML2.XMLHTTP.6.0",
                                    "MSXML2.XMLHTTP.5.0",
                                    "MSXML2.XMLHTTP.4.0",
                                    "MSXML2.XMLHTTP.3.0",
                                    "MSXML2.XMLHTTP",
                                    "Microsoft.XMLHTTP");
    // try every prog id until one works
    for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++)
    {
      try
      {
        // try to create XmlHttpRequest object
        xmlHttp = new ActiveXObject(XmlHttpVersions*);
      }
      catch(e) {}
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
    alert("Error creating the XMLHttpRequest object.");
  else
    return xmlHttp;
}
// function that displays a new message on the page
function display($message)
{
  // obtain a reference to the <div> element on the page
  myDiv = document.getElementById("myMessage");
  // display message
  myDiv.innerHTML = $message + "<br/>";
}
// function that display an error message
function displayError($message)
{
  // display error message, with more technical details if debugMode is true
  display("Un probl&egrave;me est survenue lors de la recherche du nom! Nouvelle tentative dans " +
          errorRetryInterval + " secondes." +
          (debugMode ? "<br/>" + $message : ""));
  // restart sequence
  setTimeout("process();", errorRetryInterval * 1000);
}
// call server asynchronously
function process()
{
  var xmlHttp = createXmlHttpRequestObject();
  // only continu if xmlHttp isn't void
  if (xmlHttp)
  {
    // try to connect to server
    try
    {
      // remove this line if you don't like the 'Receiving...' message
      display("Recherche en cours...");
 
      serverAddress = serverAddress + "findBy=" + document.getElementById("findBy").value +
                      "&pattern=" + document.getElementById("pattern").value;
      // make asynchronous HTTP request to retrieve new message
      xmlHttp.open("GET", serverAddress, true);
      xmlHttp.onreadystatechange = handleGettingDirectory;
      xmlHttp.send(null);
    }
    catch(e)
    {
      displayError(e.toString());
    }
  }
}
// function called when the state of the HTTP request changes
function handleGettingDirectory()
{
  display("0");
  // when readyState is 4, we are ready to read the server response
  if (xmlHttp.readyState == 4)
  {
    display("1");
    // continue only if HTTP status is "OK"
    if (xmlHttp.status == 200)
    {
      display("2");
      try
      {
        display("3");
        // do something with the response from the server
        getDirectory();
      }
      catch(e)
      {
        // display error message
        displayError(e.toString());
      }
    }
    else
    {
      // display error message
      displayError(xmlHttp.statusText);
    }
  }
}
// function that handle the response received from the server
function getDirectory()
{
  // retrieve the server's response
  var response = xmlHttp.responseText;
  // server error?
  if (response.indexOf("ERRNO") >= 0
      || response.indexOf("error") >= 0
      || response.length == 0)
    throw(response.length == 0 ? "Server error." : response);
  // display the message
  display(response);
  //restart sequence
  setTimeout("process()", updateInterval * 1000);
}

Right now it goes all the way to the handleGettingDirectory but never get the readystate ==4, what is wrong??

thanks for the help.

Cheers