Ajax Update help

[zapzack]

Can somebody help me fix this Javascript Ajax script..

function createRequestObject() {
  var ro;
  var browser = navigator.appName;
  if (browser == "Microsoft Internet Explorer") {
    ro = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    ro = new XMLHttpRequest();
  }
  return ro;
}

var feedUpdate = new Array();
var feedCount = 0;
var feedHttp = createRequestObject();
var lastFeed = null;
var lastFeedTime = 0;
var lastTopicTime = 0;
var lastTopic = null;
var response = null;

function sndFeedReq() {
	feedHttp.open('post', 'grab.php');
	feedHttp.onreadystatechange = handleFeedResponse;
	feedHttp.send(null);
}

function handleFeedResponse() {
	if (feedHttp.readyState == 4) {
		response = feedHttp.responseText;
		feedUpdate = response.split('|');
		rotateFeed();
	}
}

/*
	feedUpdate should now contain:
		0 => topic
		1 => topic time
		2 => feed
		3 => feed time
*/

function rotateFeed() {
	if (feedUpdate[0] != lastTopic || lastTopic == null || lastTopic == '') {
		if (feedUpdate[1] >= lastTopicTime) {
			lastTopicTime = feedUpdate[1];
			lastTopic = feedUpdate[0];
			if (document.getElementById("topic")) {
				document.getElementById("topic").innerHTML = "Topic: " + feedUpdate[0];
			}
		}
	}
	
	if (feedUpdate[2] != lastFeed || lastFeed == null || lastFeed == '') {
		if (feedUpdate[3] >= lastFeedTime) {
			lastFeed = feedUpdate[2];
			lastFeedTime = feedUpdate[3];
			if (document.getElementById("logo")) {
				document.getElementById("logo").innerHTML = feedUpdate[2];
			}
		}
	}
	setTimeout("sndFeedReq()", 10000);
}

sndFeedReq();

The problem seems to be at the two if's like this:

if (feedUpdate[2] != lastFeed || lastFeed == null || lastFeed == '') {

Thanks

[Y_Less]

You've said there's a problem and where you think it is, but not actually said what the problem is - what it should do and what it does do...

Two problems I do see are that if the new feed is null it will try to display it first time, and if (unlikely) the request takes longer than 10 seconds the next request will be fired on the same (global) variables.

[zapzack]

It's supposed to open grab.php, split the |'s and place some info into the main site.. And I also needed the script to be able to push new info to every user in real time.. To make it more specific.. It grabbing the live feed html and the current Chat topic from grab.php.. everytime the feed or topic changes.. i want that change to show without the user refreshing the page..