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AJAX update multiple divs from external .php's without reload

Posted on 2006-06-16
5
1,073 Views
Last Modified: 2011-01-13
Hi there,

I'm in the process of writing a small forum/message board and like to use AJAX for content updating instead of a complete refresh of the page.

I got the AJAX part running, but when updating multiple divs, the script 'collides' and the divs stop updating... Yelp?

The javascript/ajax part (ajax_test.php)

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>AJAX test page</title>
<style type="text/css">
body { font-family: verdana; font-size: 8pt; }
</style>
<script type="text/javascript">
function createRequestObject() {
    var req;
    if(window.XMLHttpRequest){
    // Firefox, Safari, Opera...
        req = new XMLHttpRequest();
    } else if(window.ActiveXObject) {
    // Internet Explorer 5+
    req = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
    // There is an error creating the object,
    // just as an old browser is being used.
        alert('There was a problem creating the XMLHttpRequest object');
    }
    return req;
}

function handleDivTag(divtag) {
    var divtag;
    return divtag;
}

function handleTimeOut(timeout) {
    var timeout;
    return timeout;
}

function handleRefresh(refresh) {
    var refresh;
    return refresh;
}

// Create the Divtag Handler -- Mainly an IE 6 Fix
var divhandler = new handleDivTag(null);
var timehandler = new handleTimeOut(null);
var refreshhandler = new handleRefresh(null);

function sendRequest(act,divtag,timeout,refresh) {
    // Make the XMLHttpRequest object
    http = createRequestObject();
    // Open PHP script for requests
    http.open('get', act);
    http.onreadystatechange = function() { handleResponse(http); };    
    // Open PHP script for requests
    divhandler.divtag = divtag;
    timehandler.timeout = timeout;
    refreshhandler.refresh = refresh;
    http.send(null);
}

function handleResponse(http) {
    if(http.readyState == 4 && http.status == 200) {
        // Text returned FROM PHP script
        var response = http.responseText;
        // document.write(http.responseText);
        if(response) {
            // UPDATE ajaxTest content
            document.getElementById(divhandler.divtag).innerHTML = response;
            setTimeout(timehandler.timeout,refreshhandler.refresh);
        }
    }
}
 
function div1() {sendRequest('page.php','div1',div1,1000); }
function div2() {sendRequest('page.php','div2',div2,1000); }
</script>
</head>
<body onload=''>
<b>div1</b><br>
<div id="div1"><?php include ("page.php") ?></div>
<br>
<b>div2</b><br>
<div id="div2"><?php include ("page.php") ?></div>
<br>
<a href="javascript:div1();">Start refreshing div1</a>
<a href="javascript:div2();">Start refreshing div2</a>
</body>
</html>

...and the content page (page.php)

<?php
echo "System time: ".date("G:i:s",time());
//sleep (1);
?>

This works fine until the refresh collides. Uncommenting the sleep statement demonstrates this perfectly...

-tnx-

Harold.
0
Comment
Question by:aling
  • 3
  • 2
5 Comments
 
LVL 18

Accepted Solution

by:
Morcalavin earned 500 total points
ID: 16919396
I'll make one suggestion.  The ajax protype library makes setting up an ajax session much much easier, and it comes with nifty little shorthand tools.

http://prototype.conio.net/
0
 

Author Comment

by:aling
ID: 16919501
I'll have a look at it... I don't want to include the whole .js since it's ~48 kb but if I can extract the functions to get the above working, I'll give it a go...
0
 

Author Comment

by:aling
ID: 16919777
Well... It works... I'll leave the test page open to check if it keeps running, but I have a good feeling about it...

The prototype.js results in such a page:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>AJAX test page</title>
<style type="text/css">
body { font-family: verdana; font-size: 8pt; }
</style>
<script type="text/javascript" src="prototype.js"></script>
<script type="text/javascript">
new Ajax.PeriodicalUpdater('div1', 'page.php', {asynchronous:true, frequency:1});
new Ajax.PeriodicalUpdater('div2', 'page.php', {asynchronous:true, frequency:1});
// make a HTTP request every 2 seconds to /foo/bar and update the 'mydiv' element.
</script>
</head>
<body onload=''>
<b>div1</b><br>
<div id="div1"><?php include ("page.php") ?></div>
<br>
<b>div2</b><br>
<div id="div2"><?php include ("page.php") ?></div>
<br>
</body>
</html>

I'll keep this post open for a few days, if nobody comes up with a smaller (<48k) suggestion, I will award you your points.

-tnx!-
0
 
LVL 18

Expert Comment

by:Morcalavin
ID: 16919836
48k isn't all that much, and it should cache, making it irrelevant in due time.  Using the 48k library will eliminate a lot of error checking on your part and provides access to some nifty shortcuts, which will make the code you have to type smaller.  So it's a tradeoff, 48k of prewritten code to save you Xk of code you don't have to type.
0
 

Author Comment

by:aling
ID: 16920008
you're right...

this works, and is well supported... And I may even use some other functions of it!

Thank you!
0

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