I don't believe it can run in a browser. I believe the only online capabilities of DBPro involve the use of client software.
However, I rarely use any of the online capabilities of DBPro, so I'm not 100% sure (More like 87%), so wait for some one else to confirm that before you make your choice.
What I
can be sure of is, if DBPro doesn't have such capabilities, You should take a look at
Java,
Flash(If you can get it fast enough to handle a full MMO(It always seems slow to me)), or
Silverlight(if you are willing to take the risk it may not work as you intended in browsers other than IE)