well,
You can code Java
You can code Mysql, and PHP
Or you can code Visual Basic
To make a game but you will need some knowledge i made a game a while back and it took me 3 - 4 days to make it cool and i killed it 2 weeks later so if your going to do this make sure you got the time and the money... it wont come cheap!
Let me answer your question with another question::confused4 HOW I CAN MAKE ONLINE GAME??????
I'm just saying it's aggravating when people type like that, because it's as though they're yelling.