@jellytriangle IE10 is supported as well, but Chrome's internal spellchecker/use of spellcheck attribute is buggy.
JCE MediaBox is an optional plugin for Joomla! 1.5 and Joomla! 2.5 which creates customizable content popups in a manner similar to the popular Lightbox and Slimbox scripts, as well as providing tooltips.
JCE MediaBox popups and tooltips are themeable and include 4 themes; Standard, Light, Shadow and Squeeze.
JCE MediaBox does not add a button to the editor toolbar. JCE plugins are used to create JCE MediaBox popups, but JCE MediaBox can be used without the JCE Editor.
Unlike Lightbox and Slimbox, JCE MediaBox can create popups to almost any type of media item, from images, to flash, quicktime,windows media files, as well as support for Youtube, Goolge Video, MetaCafe, Daily Motion, and Vimeo media links (additional types supported with add-ons), and internal and external website pages.
A full range of tutorials on creating popups for each media type is available here
Popup image on a text link
Single image popup
WebM video (supported browsers only)