setTimeout and IE6

[tomfmason]

I have posted this in a couple other forums and can't seem to find an answer to my problem..

This is a relatively minor issue but I refuse to give up on it.

Ok, I have a simple ajaxian set of functions that retrieve the current date from a backend file.

The code below works perfectly in FF, Opera and Safari..

function createRequestObject() {
    if (window.XMLHttpRequest) { // Mozilla, Safari, Opera...
        var xmlhttp = new XMLHttpRequest();
        if (xmlhttp.overrideMimeType)
	    xmlhttp.overrideMimeType('text/xml');
    }
	else if (window.ActiveXObject) { // IE
        try {
            var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
        }
    }

    if (!xmlhttp) {
        alert('Giving up :( Cannot create an XMLHTTP instance');
        return false;
    }
	return xmlhttp;
}

var http = createRequestObject();
var dtimer;


function sendRequest(option) {
     if (option !== 'first') {
	 var stopTimer = timer('stop');
     }
     http.open('GET', 'includes/process.php?action=getTime');
     http.send(null);
     try {
	   http.onreadystatechange = handleRequest;
     } catch (error) {
	   alert('the ready state is never changed');
     }
}

function handleRequest() {
      if (http.readyState == 4) {
	  var response = http.responseText;
	  document.getElementById('time').innerHTML = response;
	  var startTimer = timer('start');
      }
}

function timer(state) {
     if (state == 'start') {
	 var browser = navigator.appName;
	 if (browser == 'Micorsoft Internet Explorer') {
	     http = null;
	     http = createRequestObject();
	     try {
		  setTimeout("sendRequest('second')", 500);
	     } catch (e) {
		  alert('The Time out is not being set');
	     }
	 } else {
	     dtimer = setTimeout("sendRequest('second')", 500);
	 }
     } else {
	clearInterval(dtimer);
     }
}

I have traced it down to the fact that the handleRequest function is never being called in IE6..

As I said it works fine in every other browser except MicroShaft's..

This will work if I use setInterval but it blinks in and out every other second so that is not really an option..

Any suggestions would be great.

Thanks,
Tom

[mikemckinney]

My projects have no problems performing Ajax operations. Here's a snippet of the code I use:

    //  Configure the XMLHttpRequest object
    this.httpConnection.onreadystatechange = forwardStateChange;
    try 
        { this.httpConnection.open( requestType, ajaxUrl, true ); }
    catch (exception) 
    {
        //  URL is not in the same domain as the page        ---------------------------------
        window.alert( 'Target URL (' + ajaxUrl + ') is not in the same domain as the page.' );
        return false;
    }
    this.httpConnection.setRequestHeader( 'Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8' );
    
    
    //  Send the request  --  Need to indicate _busy_ to the user!
    this.httpConnection.send( requestParams ); 

This code actually sends a parameterized request to the server. Since you aren't sending parameters, you might be able to use simpler code.

My biggest observation is your open() function call. Try adding a third parameter of true - make an asynchronous request. I suspect that Microsoft defaults the value to false - a synchronious request. A synchronous request will not call the onreadystatechange function.

Hope this helps.....

[jimfraser]

You have to declare the onreadystatechange handler before you call the send method.