The problem with extension development is that each browser does it differently. If you abstract away the browser-specific API, it's not too hard to write a cr

The problem with extension development is that each browser does it differently. If you abstract away the browser-specific API, it's not too hard to write a cross-browser extension. Here's one that runs on both Chrome and Safari: http://code.google.com/p/marking-menu-js/source/browse/#svn%2Ftrunk http://code.google.com/p/marking-menu-js/source/browse/#svn%... Notice how it implements the important bits of Chrome's extension API in terms of Safari's: http://code.google.com/p/marking-menu-js/source/browse/trunk/safari/hostAPI.js http://code.google.com/p/marking-menu-js/source/browse/trunk... That allows you to easily port Chrome extensions over.