Thimble
© 2015 Mozilla
Thimble is a free, open source code editor for educators and students. It's designed for learning HTML, CSS, JavaScript and more. You write and edit code on the left side of the screen, and watch it spring to life on the right, in real time. To save your work you need to register and make an account. https://thimble.mozilla.org/
Windows, Mac OSX, Chrome, Internet Site
Teaches: coding, programming, html, javascript, CSS