Client v. Server - Putting a program online

Your server has some code that needs to run.
Where should the code be run: Client-side or Server-side?
We often have a lot of choice.

Demo program

Here is a demo program implemented using different choices for client-side code and server-side code.

Chaos Theory demo (explains the program)
Server-side code (visible)
(PHP)
Server-side code (hidden)
(Javascript Ajax calls PHP on server)
Client-side code
(Javascript does the calculations entirely on client side)

Comparison of different ways of putting a program online

Method	CPU load	Can access server files	Programming language	User can see source code	User input security issues	Submit opens new page	Can link to program with arguments
Server-side code (visible)	Server	Yes	Any	No	Yes	Yes	Yes. Easy.
Server-side code (hidden) (Javascript Ajax)	Server	Yes	Any	No	Yes	No	Possible but complicated
Client-side Javascript	Client	No	Javascript	Yes	No	No	Possible but complicated

On the Internet since 1987. New 250 G VPS server.

Note: Links on this site to user-generated content like Wikipedia are highlighted in red as possibly unreliable. My view is that such links are highly useful but flawed.