A game built for web is usually a folder structure containing assets. These assets include an index.html file that shows your game player, the javascript files with the game source code as well as the models, images and sounds. You need to keep this directory structure intact (even when hosted online) so that the game…
Not sure. You can still make 2D games in flash, if you know your way around coding in actionscript. There might even be game templates out there to download, if you look around a lot. Not sure if any engine can export a 3D game to swf or html5 alone. Seems unlikely to be honest, unless the file size is unbelievably huge.