JS-CodeEdit is a JavaScript editor that converts your HTML textareas into a code editor with realtime syntax highlighting. If added into a form, the content can be submitted e.g. to be written to a file. A nice thing is that you can add as many editors as you want within a HTML page.
Currently the code editor supports the following languages: PHP, JavaScript, HTML, CSS.
According to WikiPedia:
Syntax highlighting is a feature of some text editors that display text—especially source code—in different colors and fonts according to the category of terms. This feature eases writing in a structured language such as a programming language or a markup language as both structures and syntax errors are visually distinct. Highlighting does not affect the meaning of the text itself; it’s made only for human readers/editors.
SyntaxHighlighter 2.0 is one of the most popular fully functional self-contained code syntax highlighter developed in JavaScript. Alex Gorbatchev started this project in 2004 and since then has gained a lot of acceptance. Version 2.0 comes with a near complete rewrite, clean up, optimization, standard compliance and new features.
Features include:
GeSHI is a Generic Syntax Highlighter that aims to be a simple but powerful highlighting class. Initially, it was started as an idea to create a generic syntax highlighter for the phpBB forum system, but has been generalized to this project.
Features include:
GeSHi aims to do this all as quickly as possible. Many customisable features of GeSHi facilitate speed increases, and you can easily find a balance between the amount of highlighting done and the speed in which it is done.