Caffeine is a livecoding environment for the web. After adding it to a webpage, you can use it to change that page live, without reloading, and to store your changes. You can interact with Caffeine through a full graphical interface inside your page, and with your favorite text editor. Learn more at: https://caffeine.js.org.
This page is an early demo of running Pharo 6 with the SqueakJS virtual machine. It gets far enough now that I think several people in the Pharo community could fix the rest of the bugs (mostly missing primitives).