This repo contains a story about an iframe, designed to illustrate postMessage communication. The story.txt contains references to HTML documents 0-4.html that demo each respective step of the process.
To 'use' this repo, serve locally and access each of the files at http://parent.127.0.0.1.xip.io:8000/0.html
xip.io is a DNS resolver that returns whatever IP address is given, a convenient alternative to hostfile editing.