blocked a frame of origin "null" from accessing a cross-origin frame - chrome

This happens because Chrome doesn't allow frames from your hard disk to access each others' content. Which, technically we term as Cross-origin request.

Solution of the above problem is:

1. Either you host your webpage on a local web server. See the following link:
What is a faster alternative to Python's http.server (or SimpleHTTPServer)?

2. Use any other browser like Firefox

If you use Visual Studio Code, you can install an extension named "Live Server". It helped me when I had the same problem.

If you don't want to use a local web server as suggested in the accepted answer you can run the browser with cross domain web security / same origin policy disabled.

For Chrome:

Disable same origin policy in Chrome

For Firefox:

Disable cross domain web security in Firefox

https://addons.mozilla.org/en-US/firefox/addon/access-control-allow-origin/

Disable firefox same origin policy