HTML5 or Flash for online games

HTML5 or Flash for online games

I want to make games in C++/OpenGL and port them to Web via:
Crossbridge (Flascc)
emscripten (HTML5/JS)
Which route should I take? Both have pros and cons:
AS3:
Huge user base.
SWF can be encrypted via say mochi encrypt, so it is tough to break site
locks/steal code etc
3D graphics run via Stage3D which runs on huge number of machines and
browsers.
JS/HTML5:
Not as much userbase as AS3 ??
Probably no way to sitelock the game, all code and assets visible. Much
less secure than AS3 ??
3D graphics run via WebGL, which I guess is not as exposed as Flash Stage3D ?
Apart from the cons, i've seen a few decent sized MMO/RPG games running in
HTML5. How do they manage the site locks, content/code theift etc?
I am not worried about sponsorships at all (or even pre-game ads). I just
need to increase traffic on my website. The games will be multiplayer in
the near future.
So which route should I go ? Crossbridge (Flash) or emscripten (JavaScript) ?