Developing an extension that runs just in one browser is already an endeavour. If you for some reason have to create an extension that works with multiple browsers the horror gets real. Thanks to frameworks like BabelExt it might just be a lot easier. BabelExt is a framework, that allows you to write code from which you can generate an extension for Chrome, Firefox, Safari and Opera. It’s been started by the developer of the famous RES extension, honestbleeps. The main focus of the framework is page modification, so if you want to do user interface stuff, you’ll have to look for another framework, but there are existing solutions, too.
Cross-Browser Extensions with BabelExt
