The idea is good, but it depends what you want to make. For example, if you want to make a client lightweight, with a decent framerate, then expect only to transfer lines and cirkels. If you want to make a full blown game with orcs fighting and with flying space ships, then it's a different story.
The main problem is to have a server running for 24/7, this cost money.
The best thing is to look into Sockets. But i am unsure if Sockets work with ProcessingJS. I think not.

Thank you for your reply, el_dippo.  The situation is I would like to present full quality image graphics at whatever framerate is possible, for use in gaming and other applications.  It might be good to have some alternatives as to the method of graphics delivery that could be configurable such that the server supports all modes and the clients may differ and have different modes.  

Ok, sounds cool. What i tried to explain, is when the content is static, the solution is easier. When the content is non static, the solution is very hard. (example : YouTube is non static)
Because you don't tell the goal of your project, you can make a sister project that contains the most important solutions for your main project. Except, we need to know the goal of the sister project. :)

If you want a handle to how to make client / server connection, buy the book "Head First Java" (chapter 15). I have not played enough with this chapter because it is pretty advanced and i need a project/goal and a server.

el_dippo, thank you for your reply, the sister project is a fine idea indeed.  A good sister project could be a 3D pong game.  In this game, the client is given a choice of having the video perspective of a player, the puck, a paddle, or a spectator.  A different set of game controls, typically keyboard and mouse but also possibly including other HID devices exists for each role.  The server must render a separate perspective for each of the occupied client viewer roles and then send the resulting video stream to the client.  The server must also respond to commands from the clients which do things like play the pong game and move the viewing location and angles of the spectator(s), etc.  

Oh, another thing comes to mind.  You mention that you need a server to study chapter 15 of the Java book which contains advanced information on how to accomplish this goal.  I suppose it would be fairly easy for me to just make an account on my server for you to use temporarily while you do your studying, that is if the end goal is to produce a library or some code snippets that implement one or more video streaming protocols.  I would have to know a bit more about you by email or Skype or telephone before doing that, which is easy enough.