WYSIWYG Editor With A File Manager: elRTE
elRTE is an open source and feature-rich WYSIWYG editor that is built using jQuery UI.
It performs all standard functions of an editor and has all the extras like undo-redo, advanced table management, creating a custom HTML element with a custom style + inserting it quickly and more.
The interface is controlled via a single CSS file and can be customized pretty easily.
It has a built-in "save" button which can be attached to a JS function that saves the content that is pretty useful for helping users not to lose their content.
elRTE can be integrated with any file manager, however, there is elFinder, a file manager that has ready-to-use integration (can be used standalone too).
Compatibility: All Major Browsers