CodeMirror

http://codemirror.net/

CodeMirror 是一款“Online Source Editor”，基于Javascript，短小精悍，实时在线代码高亮显示，他不是某个富文本编辑器的附属产品，他是许多大名鼎鼎的在线代码编辑器的基础库。

CodeMirror is a JavaScript component that provides a code editor in the browser. When a mode is available for the language you are coding in, it will color your code, and optionally help with indentation.