Online Game

Hi im trying to make a chat room/ball game…
for demo go to silverneo188.tripod.com/games(no www.) then flying crisis.
I want it to where if another person plays the game somewhere else it adds there ball to the game, and when they leave their ball dissapears

The second part is I want it to where if a person types something in the text box the word they typed would go above their head and dissapear after a few seconds.

please help, im a noob on making multiplayer games…