[insteadof]

Seems only Chrome exists as a browser. All others need not apply.

[xxbondsxx]

Should work on Firefox, Chrome, and Safari. Anything specific you are noticing in another browser??

I rely pretty heavily on the box model for layout, but if you look at the CSS I included almost every browser extension (even Opera)

[rexreed]

It doesn't really layout well in my version of Firefox (18.0.2) - see the output here: http://imm.io/WxqQ and here: http://imm.io/Wxr8

You can't see what's happening and the box seems to be improperly sized and spaced as well as problems with the terminal-style text editing window. The text flows off the bottom and cursor is misaligned: http://imm.io/WxrS

[pbhjpbhj]

Same, here FF 18.0 on Ubuntu. Unusable.

[test001only]

http://imgur.com/XvK3kFY - the layout of the box is messed up in Firefox. Using Firefox version - 18.0.2. Works great in chrome though. Thanks for the nice tutorial!

[jazz]

For example the buttons does not work in the levels dialog. I would make a pull request if I could figure out how to build it with Grunt...

[xxbondsxx]

Fixed! Totally my bad, click event properties are super browser-specific

[jazz]

jQuery is here for that... You should use event.target.