Yes, we want to add support for editing JavaScript directly in Puzlet Web Lab (it's particularly useful for copy/pasting snippets). We've found, however, that

Yes, we want to add support for editing JavaScript directly in Puzlet Web Lab (it's particularly useful for copy/pasting snippets). We've found, however, that writing scientific computing code is much more succinct in CoffeeScript. Moroever, it is fully compatible with all JS libraries. Note also that you can see generated JS by clicking the "JS" toggle button in Puzlet Web Lab.