title: Access Unity Webgl output from browser and vice versa
body: <p>I receive a package of Unity webgl and put that into a course in Wordpress. The index.html produced form Unity is accessed inside an iframe there. This must be able to count user click when accessing the course.</p>
  
  <p>The Unity developer only said that the variable is Click and there is also information: </p>
  
  <pre><code>Application.ExternalCall("Send_Clicks", clickCount.ToString());
  </code></pre>
  
  <p>I read Unity documentation, I should create a js script to retrieve the message from Unity. How to retrieve the message from Unity? Where do the script should be placed?</p>
  
  <p>Any answers are greatly appreciated. Thank you.</p>