Javascript callback when IFRAME is finished loadin

Question

I need to execute a callback when an IFRAME has finished loading. I have no control over the content in the IFRAME, so I can't fire the callback from there.

This IFRAME is programmaticly created, and I need to pass its data as a variable in the callback, as well as destroy the iframe.

Any ideas?

EDIT:

Here is what I have now:

function xssRequest(url, callback)
{
    var iFrameObj = document.createElement('IFRAME');
    iFrameObj.src = url;            
    document.body.appendChild(iFrameObj);   

    $(iFrameObj).load(function() 
    {
        document.body.removeChild(iFrameObj);
        callback(iFrameObj.innerHTML);
    });
}

This callsback before the iFrame has loaded, so the callback has no data returned.

Answer 1

I wanted to hide the waiting spinner div when the i frame content is fully loaded on IE, i tried literally every solution mentioned in Stackoverflow.Com, but with nothing worked as i wanted.

Then i had an idea, that when the i frame content is fully loaded, the $(Window ) load event might be fired. And that exactly what happened. So, i wrote this small script, and worked like magic:

     $(window).load(function () {
     //alert("Done window ready ");
     var lblWait = document.getElementById("lblWait");
     if (lblWait != null ) {
         lblWait.style.visibility = "false";
         document.getElementById("divWait").style.display = "none";
     }
 });

Hope this helps.

Answer 2

I've had exactly the same problem in the past and the only way I found to fix it was to add the callback into the iframe page. Of course that only works when you have control over the iframe content.

Answer 3

I am using jQuery and surprisingly this seems to load as I just tested and loaded a heavy page and I didn't get the alert for a few seconds until I saw the iframe load:

$('#the_iframe').load(function(){
    alert('loaded!');
});

So if you don't want to use jQuery take a look at their source code and see if this function behaves differently with iframe DOM elements, I will look at it myself later as I am interested and post here. Also I only tested in the latest chrome.

Answer 4

I think the load event is right. What is not right is the way you use to retreive the content from iframe content dom.

What you need is the html of the page loaded in the iframe not the html of the iframe object.

What you have to do is to access the content document with iFrameObj.contentDocument. This returns the dom of the page loaded inside the iframe, if it is on the same domain of the current page.

I would retreive the content before removing the iframe.

I've tested in firefox and opera.

Then i think you can retreive your data with $(childDom).html() or $(childDom).find('some selector') ...

Answer 5

I have a similar code in my projects that works fine. Adapting my code to your function, a solution could be the following:

function xssRequest(url, callback)
{
    var iFrameObj = document.createElement('IFRAME');
    iFrameObj.id = 'myUniqueID';
    document.body.appendChild(iFrameObj);       
    iFrameObj.src = url;                        

    $(iFrameObj).load(function() 
    {
        callback(window['myUniqueID'].document.body.innerHTML);
        document.body.removeChild(iFrameObj);
    });
}

Maybe you have an empty innerHTML because (one or both causes): 1. you should use it against the body element 2. you have removed the iframe from the your page DOM

Answer 6

The innerHTML of your iframe is blank because your iframe tag doesn't surround any content in the parent document. In order to get the content from the page referred to by the iframe's src attribute, you need to access the iframe's contentDocument property. An exception will be thrown if the src is from a different domain though. This is a security feature that prevents you from executing arbitrary JavaScript on someone else's page, which would create a cross-site scripting vulnerability. Here is some example code the illustrates what I'm talking about:

<script src="http://prototypejs.org/assets/2009/8/31/prototype.js" type="text/javascript"></script>

<h1>Parent</h1>

<script type="text/javascript">
function on_load(iframe) {
  try {
    // Displays the first 50 chars in the innerHTML of the
    // body of the page that the iframe is showing.
    // EDIT 2012-04-17: for wider support, fallback to contentWindow.document
    var doc = iframe.contentDocument || iframe.contentWindow.document;
    alert(doc.body.innerHTML.substring(0, 50));
  } catch (e) {
    // This can happen if the src of the iframe is
    // on another domain
    alert('exception: ' + e);
  }
}
</script>
<iframe id="child" src="iframe_content.html" onload="on_load(this)"></iframe>

To further the example, try using this as the content of the iframe:

<h1>Child</h1>

<a href="http://www.google.com/">Google</a>

<p>Use the preceeding link to change the src of the iframe
to see what happens when the src domain is different from
that of the parent page</p>