That's cool but I'm unsure if I want to learn Java. -- I guess no C++ IDE are available for such?

EDIT: removed link since it had nothing to do with your question.

[Actually, if you're already familiar with c++ the step to java is fairly trivial so don't rule it out as an option]

HTML is hyper text markup language, basically it can only be used to displaying text and images to the screen. Any interactivity like buttons changing colours as they are highlighted need javascript or similar. Javascript is quite neat as it can be types into an HTML document and then any javascript supporting browser can execute it, in theory this should be all modern graphical browsers (yeah you can get command line browsers too) however certain mobile browsers are sometimes a little iffy with it.

Alternative options if you want games on the web playable in browser:
Flash and java can both be used. Unity now has its web player browser plug-in too although I haven't checked if that is a free or pro feature. All 3 of course require that the user has the relevant plugins however most computers now will have flash player and java already or most browsers are capable of alerting the user that they need to get flash or java and will provide a link.


Theres other options too but these are the main ones (apart from unity, not seen that in action yet)



EDIT: heres a thread about a game made with HTML and javascript: http://www.gamedev.net/topic/621477-old-school-racing-topgear-lotus-game-track-algorithm/

I've recently started a tutorial series for Cocos2D HTML5, and HTML5 ( meaning Javascript + Canvas tag ) port of the ever popular cocos2D library. If you want to make browser games, that is a very good place to start. It's still in development though, so expect some changes ( already happened in my tutorials .node() is now .create() ).