有没有好的浏览器内代码编辑器?

We've all seen in-browser rich text editors, which allow you to edit colored/styled text in a WYSIWYG manner. But what about code editors, which automatically highlight code based on language rules as you type? Think Eclipse in a textarea (but without the refactoring support).

Do such things exist? I imagine scaling would be a problem - larger files would be difficult to edit efficiently.

解决方案

CodeMirror comes with support for 60+ languages, and addons that implement more advanced editing functionality (autocompletion, code folding, configurable key bindings, search & replace, linter integration etc.). A rich programming API and a CSS theming system are available for customizing CodeMirror, and extending it with new functionality.

It has been developed since early 2007, has a Wikipedia page, and is being used in a wide number of popular open source projects (Joomla, Firebug etc.).