Javascript --> iframe resizing using postMessage method

Question

I'm trying to understand another Stackoverflow answer ( cross-domain iframe resizer? ) that purports to solve how to resize an iframe (hosted on a domain separate from the domain it's embedded in) according to its height. Wondering if anyone could answer my questions below.

THE SOLUTION:

Iframe:

 <!DOCTYPE html>
<head>
</head>
<body onload="parent.postMessage(document.body.scrollHeight, 'http://target.domain.com');">
  <h3>Got post?</h3>
  <p>Lots of stuff here which will be inside the iframe.</p>
</body>
</html>

The parent page which contains the iframe (and would like to know its height):

<script type="text/javascript">
   function resizeCrossDomainIframe(id, other_domain) {
    var iframe = document.getElementById(id);
    window.addEventListener('message', function(event) {
      if (event.origin !== other_domain) return; // only accept messages from the specified domain
      if (isNaN(event.data)) return; // only accept something which can be parsed as a number
      var height = parseInt(event.data) + 32; // add some extra height to avoid scrollbar
      iframe.height = height + "px";
    }, false);
  }
</script>

<iframe src='http://example.com/page_containing_iframe.html' id="my_iframe"     onload="resizeCrossDomainIframe('my_iframe', 'http://example.com');">
</iframe>

MY QUESTIONS:

http://target.domain.com refers to the domain the iframe is
embedded within, right? NOT the domain that the iframe is hosted on?
In the function resizeCrossDomainIframe(id, other_domain) { line, I'm not supposed to interchange "id" with the id of the iframe and "other_domain" with the domain name that the iframe is hosted on, right? They're only parameters that I specify later when I call the function.
Instead of using onload within the iframe tag, I wrote the equivalent in jQuery, which loads on the page that embeds the iframe:
$('#petition-embed').load(function() { resizeCrossDomainIframe('petition-embed','http://target.domain.com'); });
I added brackets around return:
if (event.origin !== other_domain) {return;} // only accept messages from the specified domain if (isNaN(event.data)) {return;} // only accept something which can be parsed as a number

Does that look right?

Answer 1

I needed to do something similar, and found this example that seems simpler: using postmessage to refresh iframe's parent document

Here is what I ended up with in the iframe:

window.onload = function() {
  window.parent.postMessage(document.body.scrollHeight, 'http://targetdomain.com');
}

And in the receiving parent:

window.addEventListener('message', receiveMessage, false);

function receiveMessage(evt){
  if (evt.origin === 'http://sendingdomain.com') {
    console.log("got message: "+evt.data);
    //Set the height on your iframe here
  }
}

Javascript --> iframe resizing using postMessage method

Question

1 answers

solution1
2 2014-01-24 18:46:31

Javascript --> iframe resizing using postMessage method

Question

1 answers

solution1 2 2014-01-24 18:46:31

solution1
2 2014-01-24 18:46:31