Specifically for JS, CSS, HTML: what is the difference between optimization, compression, minification, tidying, concatenation?

Question

When we talk about source code and the file which contains the code like CSS, HTML, JavaScript and we also talk about performance of a web site or application, what is the differences between these terms?

• Optimization
• Compression
• Minification
• Tidying
• Concatenation

Answer 1

• Optimization - general term meaning any of the following:
• Compression - fewer bytes through algorithmic means
• Minification - fewer bytes by using shorter syntax with the same meaning
• Tidying - removing code that doesn't do anything and removing redundant code
• Concatenation - delivering all the data in one request rather than multiple requests

• Jitendra Vyas: +1 Thanks can you give a simple example of each using a simple css code?
• Raynos: Is Minification the same alpha conversion? (lambda calculus). Also code that doesnt do anything is also known as "dead code"
• Loki Astari: @Raynos: 'DeadCode' is covered under Tidying. Minification would be replacing while(true) with for(;;) (both loop forever but the second one is 4 bytes shorter).
• AndyMcKenna: @Jitendra: Compression - gzipped. Minification - code rewritten to be less characters but still work. Internal variables might be changed from "theXYCoordinate" to just "a". Tidying - can't get simpler than what Scott said. Concatenation - you might combine jquery, jquery ui, and your own JS all into one file. It's all the same code but 1 HTTP Request instead of 3.
• Jitendra Vyas: @Andy - +1 How to do these things with any website I develop.