PostMessage issues in SL360

Hi! 

I have to link an embedded interactive video to SL. For this I want to use the PostMessage() method from iframe to parent. With the little experience I have in Javascript I first had to find out the basics. Now I'm able to get the connection working in html with two different domains, send a message and check if the condition of the message is right before executing anything.

For this I used the following javascript code. 

//script used in the body of the iframe:

<script>
     window.onload = function(e){
          parent.postMessage('test', '*http://www.url.com');
     };
</script>

// *i've changed the url for this message 

//script used in the body of the HTML parent:

<script>
     window.addEventListener('message',function(e){ 
          if(e.data == 'test'){ 
               alert('true'); 
               console.log('message received...'); 
               console.log(e); 
          }
     });
</script>


//script used in Storyline onClick Execute Javascript trigger:

window.addEventListener('message',function(e){ 
     if(e.data == 'test'){ 
          alert('true'); 
          console.log('message received...'); 
          console.log(e); 
     }
});

In SL I've inserted the same iframe. I've created a simple button to trigger the script. I've published to web and uploaded it to the same domain as the parent HTML I mentioned before. Unfortunately it doesn't work. Does anyone know what I'm doing wrong? Can anyone help me? 

//I'm getting this message in the developer console while testing in Chrome

app.min.js:32 Uncaught TypeError: Cannot read property 'request' of undefined
 at t.onVolumeChanged (app.min.js:32)
 at c (app.min.js:11)
 at Object.trigger (app.min.js:11)
 at t.onVisibilityHidden (app.min.js:47)
 at c (app.min.js:11)
 at Object.trigger (app.min.js:11)
 at HTMLDocument.<anonymous> (app.min.js:47)