Ah sorry for not being too specific.

The game i would like to be building are online real time based.
Meaning playing online with other players, rating/score changes depending what the user does, etc etc.

Basically, a multiplayer game just like runescape where you can play with other players.

Thanks

Then you pretty much want to use Unity, Java, Flash or Silverlight (With Java and Silverlight being the most flexible and Flash having the largest installbase), If you think you can get away with requring a download and installation for your game and need to use OpenGL4/DX11 features then Java or Unity pro is the way to go, If DX9/OpenGL2.1 level features are enough then Flash, or the free version of Unity is good enough. (Unity is probably the easiest option out there for this kind of thing), I wouldn't use Javascript for a serious project today, (It might end up being the standard way to do webgames in the near future though and it can do some really amazing things if you don't mind wrestling with the inconsistent browser support)

The server can be written in almost any language (Allthough php is a bad choice for it as its not really designed for that kind of use)

How can i know if this will work fine for me and what are the steps to be taken?

Prototype, measure, extrapolate.

Also, profiling. A good code profiler is almost guarenteed to speed up your program - And don't forget the uttility if just timing functions and printing the time it took.

That's how I got one function down from 1.76 seconds per iteration to 0.09 seconds per iteration. (It had lots of memory allocations)

I would like to thank you all with all the help!

I decided to give it a try, using HTML5 + JavaScript.
I finished learning HTML5, practicing here and there and i am now in the middle of my JavaScript reading.

After much work put into it, i am starting to wonder if JavaScript is going to be fast enough for my online/multi-player needs.

Can anyone help me out on this?
How can i know if this will work fine for me and what are the steps to be taken?

Thanks once again!

Performance wise it depends on several factors:
1) Which browser the users is running (Javascript performance varies greatly between between browsers, newer browers tend to perform alot better in this area).
2) How much actual work you need to do on the client.
Quake 2 has been ported to Javascript and runs well in chrome and firefox (not at all in IE since it requires webgl) so you can do quite alot on the clientside of things without running into performance issues.

The big problem for an MMO is scalability and that is mostly a serverside and network problem, The actual performance of the language implementation you use isn't all that important as long as you can throw more hardware at it(and hardware is cheap), The biggest concern should always be bandwidth for a project like this as it is awfully expensive. Bandwidth requirements doesn't increase linearly, doubling the number of players will more than double your bandwidth needs (worst case is just over 4x the bandwidth for 2x the players) so for any game at the MMO scale (thousands of players) this is critical.

I am still learning and i am not sure what this means

He is saying implement a quickie version of your game, seem if the performance is good enough and react accordingly.


Aka, jump in and find out.