Many GitHub repositories don't use GitHub Pages to host their HTML files. GitHub & BitBucket HTML Preview allows you to render those files without cloning or downloading whole repositories. It is a client-side solution using a CORS proxy to fetch assets.
If you try to open raw version of any HTML, CSS or JS file in a web browser directly from GitHub, all you will see is a source code. GitHub forces them to use the "text/plain" content-type, so they cannot be interpreted. This script overrides it by using a CORS proxy.
In order to use it, just prepend the below fragment to the URL of any HTML file. Copy and paste below:
https://htmlpreview.github.io/?- https://htmlpreview.github.io/?https://github.com/twbs/bootstrap/gh-pages/2.3.2/index.html
- https://htmlpreview.github.io/?https://github.com/documentcloud/backbone/blob/master/examples/todos/index.html
What it does is: load HTML using CORS proxy, then process all links, frames, scripts and styles, and load each of them using CORS proxy, so they can be evaluated by the browser.
GitHub & BitBucket HTML Preview was tested under the latest Google Chrome and Mozilla Firefox.
© 2019 Jerzy Głowacki under Apache License 2.0.