To chip in on this: I found writing for Undum absolutely horrible until I made a tool, because JS is a language full of punctuation and with a very slow test/debug cycle. (The HTML tag thing I released earlier is because, if you get your tags wrong, that bit of content disappears silently. If you can live with that, great, but I couldn’t.)
For the games I’ve written I’ve used a perl script to turn a plain-text format into the .game.js file.
The perl script will get a release soon, once I’ve documented it properly. It’s grown to be pretty powerful, so that’s taking longer than I’d hoped. Also, it requires some changes to the undum.js file where I’ve added features, so I need to tidy that up too.
Anyway, once done, you release by copying the entire file-structure from Undum down to a server or something, and make your games main .html page by copying the example and changing the .game.js file it points to.
For authoring on a Mac I can’t rave enough about TextWrangler, which is free, does syntax colouring for js (especially helpful if you’re writing it straight), as well as html and perl and others, and it can run a perl script on a keypress (Apple-R). Perl script + TextWrangler = IDE.
I think Undum is fantastic, and it’s opened a lot of creative doors for me. I think it’s well worth a hike up the learning curve for. 