An anonymous reader tips news that, right on schedule after Tuesday's Firefox 8.0 launch
, Mozilla has rolled out the beta of Firefox 9.0
, UI improvements for the OS X Lion version, and Do Not Track opt-out detection for developers. 9.0 beta also "supports chunking for XHR requests so websites can receive data that’s part of a large XHR download in progress. This helps developers make websites and Web apps faster, especially those that download large sets of data or via AJAX."