WIODE is an open source and web-based IDE application which focuses on simplicity and expandability.
WIODE is a web-based open source IDE built as a replacement for the standard desktop-installed IDE’s. The aim of the WIODE project is to create and maintain a versatile ‘base’ IDE that installs quickly and can be customized by anyone using it to make it their own.

It is built with PHP-MySQL and has an interface that will feel familiar to anyone working with desktop IDEs.
The application is very easy to work with; it can manage multiple projects, a file-tree helps browsing files-folders where double-clicking an item is displayed in a new tab (multiple tabs, yay!).
Right-clicking on files/folders (context menu) brings options like “create copy, rename, delete or “FTP upload“.
For the opened files, there are features like syntax highlighting, line numbering, auto-indenting, saving and previewing.
Also, a “system” menu displays the lists of projects, number of files in each and presents options like taking backups or archiving them.
WIODE is a multi-user application where users can work at the same time without overwriting each other’s files.
Checkout Wiode in action video.
Requirements: PHP 5+ and MySQL 5+
Compatibility: All Modern Browsers (except IE)
Website: http://www.wiode.com/
Download: http://www.wiode.com/download