title: I want to access Popup functions(window.open) with different domain
body: <p>I want to access Popup function(child). but Their domain is different!
  Error code is below</p>
  
  <pre><code>Uncaught DOMException: Blocked a frame with origin "xxxx.xxxx.xxx" from accessing a cross-origin frame.
  </code></pre>
  
  <p>I try remove subdomain. and access popup fuction. </p>
  
  <pre><code>document.domain="xxxx.kr";
  </code></pre>
  
  <p>i Know / Can do this!</p>
  
  <p>but Now Their domain is only different!!</p>
  
  <p>How can I solve this problem?</p>
  
  <p>Questions is below!
   1. I want to Access Pop Up(different domain) function!</p>