javascript postMessage - test the reception of message

Question

I use postMessage to communicate between an host and an iframe of my domain.

Here is the code on the hostdomain.org:

function rec_tyd(json_var)
{
  //if i decode and alert json_var there i get the content.
  var win = document.getElementById("tyd_frame").contentWindow;
  win.postMessage(json_var, "http://multipress.fr/tyd//module/pro_mod.php");
}

<iframe src="http://example.org/myiframe.php" width="500" height="200" 
name="tyd_frame" id="tyd_frame" style="border:1px solid black;"</iframe>

json_var is a JSON object.

And the code on my domain, example.org/myiframe.php is:

if (!window.addEventListener)   // IE
  {window.addEventListener = function (type, listener, capt) {
  attachEvent("on"+type, function(){listener(event)});}
}

addEventListener("message", function(e) {       
  var final = JSON.parse(e.data);
  alert(final.id_product);
  alert(final.id_company);
}, false);

Basically, everything is working except:

• at the first load, I don't get anything in the iframe
• when I reload once, I get the value
• if I refresh the hostpage, I get nothing again.

Same thing in Chrome and FireFox: refresh doesn't work, but if go in the address bar and press enter, it works. Except for the first time.

I checked my JSON object, and I get it before the postmessage. It's really in the iframe that I get nothing.

So my question is: how can I test that I get something? Did I made a mistake in my code?

Currently I'm actually working on the same domain but it will be on a different domain for production.

Answer 1

Solved in the comments :)

==> Stop launching my postMessage when document ready but put it in the onload status of the iframe and it seems that the problem is fixed ! Thanks