I am not POSSITIVE but it looks like you can do to your projects and edit the game then upload another file (which would be the webGL version of the game that I assume you already have). if that doesn't work try looking on YouTube
there was an option on the game page to switch from "games will be downloaded" to "play in browser" or something like that. then when uploading the webgl zip it let me switch to play online under the file options
