How to disable cross domain js ban?

Question

JavaScript

I want to parse the MTS website in JS from the browser. It is necessary that this code works from any or at least a predefined domain.

var MTS = window.open("https://login.mts.ru", "MTS");
setTimeout(function(){ // onload не слушается, пока что будет таймер
  console.log(MTS.document.body.innerHTML); // забираем body
},5000);

Googled that some browser extensions solve this problem. but none of them helped me. Apparently I'm doing something wrong. Please explain on your fingers what to download and how to run so that cross-domain materializes.

Answer 1

https://chrome.google.com/webstore/detail/allow-co...
UPD:
Under windows, create a shortcut, or run from cmd

chrome.exe --user-data-dir="C:/Chrome dev session" --disable-web-security

On Linux, after killing all chrome processes:
chromium-browser --disable-web-security