There are many different plugins used to play free online games.
Some of these are the Java virtual machine, Shockwave, Flash and
There are specialised tools used to create free games employing
these technologies. FreeGames that require plugins are usually based
on the client-side; that is, much of the processing is done by the
player's computer instead of the server hosting the free game.
However, there are also server-side freegames which do not require
plugins and process the data on the game server instead of the player's
computer. These free games are typically not as pulchritudinous
as client-side based games, but make up for that in advanced functionality,
particularly because it is easier to implement multiplayer capabilities.
BattleMaster is an example server-side game.
Hybrids of server- and client-side games also exist.