Detect if the iframe content has loaded successfully

Question

I have a widget that contains an iframe. The user can configure the url of this iframe, but if the url could not be loaded (it does not exists or the user does not have acce

Answer 1

How about checking if the url is available and only then setting the actual url of the iframe? e.g. with JQuery

var url = "google.com"
var loading_url = "/empty.html"
document.getElementById("iframe").src = loading_url;
$.ajax({
    url: url,
    type: 'GET',
    complete: function(e, xhr, settings){
         if(e.status === 200){
              document.getElementById("iframe").src = url;
         }
    }
});

Edit: This does not seem to work cross domain, the status code is 0 in those cases.

Answer 2

I found the following link via Google: http://wordpressapi.com/2010/01/28/check-iframes-loaded-completely-browser/

Don't know if it solves the 'Page Not Found' issue.

<script type="javascript">
var iframe = document.createElement("iframe");
iframe.src = "http://www.your_iframe.com/";
if (navigator.userAgent.indexOf("MSIE") > -1 && !window.opera) {
  iframe.onreadystatechange = function(){
    if (iframe.readyState == "complete"){
      alert("Iframe is now loaded.");
    }
  };
} else {
  iframe.onload = function(){
    alert("Iframe is now loaded.");
  };
}
</script>

I haven't tried it myself, so I don't know if it works. Good luck!

Answer 3

Nowadays the browsers have a series of security limitations that keep you away from the content of an iframe (if it isn´t of your domain).

If you really need that functionality, you have to build a server page that have to work as a proxy, that receive the url as a parameter, test if it is a valid url, and does the redirect or display the error page.

Answer 4

If you control the content of the iframe, the iframe can send a message to the parent.

        parent.postMessage('iframeIsDone', '*');

The parent callback listens for the message.

        var attachFuncEvent = "message";
        var attachFunc = window.addEventListener ;
        if (! window.addEventListener) {
            attachFunc = window.attachEvent;
            attachFuncEvent = "onmessage";
        }

        attachFunc(attachFuncEvent, function(event) {
            if (event.data ==  'iframeIsDone') { // iframe is done callback here
            }
        });

Answer 5

If you have control over the contents of the iframe (e.g. you can add arbitrary code to the page), you can try to implement a special function in each of them, then in your page, you call that function and catch an error (via window.onerror handler) if the function called via eval fails because the page didn't load.

Here's example code: http://www.tek-tips.com/viewthread.cfm?qid=1114265&page=420

Answer 6

After the onload fires, you can scavenge the content of the iframe to see if it contains a usefull page or not. You'd have to make this browser specifuc unfortunately because they all display a different "page not found" message.

For more info, take a look here at http://roneiv.wordpress.com/2008/01/18/get-the-content-of-an-iframe-in-javascript-crossbrowser-solution-for-both-ie-and-firefox/