MooEditable is a MooTools plugin that instantly converts a textarea field into a WYSIWYG editor.

It has a slick interface & comes with only the frequently used items like text formatting, lists, inserting images/links & undo/redo.

The plugin can also switch between design & HTML modes.

If you'd like to improve it further or customize to your needs,  It has a very detailed documentation.

MooTools WYSIWYG Editor

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