Advanced Code Editor

[iframe src=”https://www.evernote.com/shard/s14/sh/8bf13f00-70eb-4249-92bc-74d3deef93f1/0ec6e5c7e70a416c5716dcfbc2369715″ scrolling=”yes”]

This one is good for digging in and editing the code in ways that are useful.

Link- http://wordpress.org/extend/plugins/advanced-code-editor/

Enables syntax highlighting in the integrated themes and plugins source code editors. Supports PHP, HTML, CSS and JS.
Effectively edit your themes or plugins when you only have access to a browser, by enabling syntax highlighting in WordPress integrated source code editors. Supports PHP, HTML, CSS and JavaScript
Features
Mixed language Syntax highlighting (PHP,HTML,JavaScript and CSS)