Name explains it
Yes, you can - as long as the export works in the browser without any extra plugins you are good to go.
Alright, the name Gamedev.js confused me and made me think I needed to use JS. Thanks for confirming.
Gamedev.js is mainly a community of HTML5 game developers and JavaScript programmers, but we wanted to have a broad game jam for anyone who can build a game for the web, so anything that exports to JavaScript and works in the browser will be ok.
