New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  actions: {
    clickFunction: function() {
      var parentWindow = window.parent;
      console.log("window of iframe", window);
      console.log("parent window", parentWindow);
      console.log("parent window cookie before setting", parentWindow.document
        .cookie);
      parentWindow.document.cookie = "testkey=testValue";
      console.log("parent window cookie", parentWindow.document.cookie);
    }
  }

my-route.route.js

import Ember from 'ember';

export default Ember.Route.extend({
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<button {{action "clickFunction"}}>Click</button>
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.4.0",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.5/ember.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.5/ember-data.js"
  }
}