Apple released a public beta of Safari 4 on Tuesday, promising a much faster browser with improved navigation and searching.
The newest edition of the browser will run JavaScript commands 4.2 times faster than Safari 3, the company said in a statement. Safari 4 will also deliver better JavaScript and HTML page-loading than Microsoft's Internet Explorer 7 or Mozilla's Firefox 3, Apple added.
The beta is available for download at Apple's Safari web page, with both Windows and Mac OS versions ready for testing. Mac users need to be running Mac OS X Leopard 10.5.6 and Apple's latest security update, or Mac OS X Tiger 10.4.11, on an Intel Mac or a G3 or better Mac. Windows users need Windows XP SP 2 or Vista.
Apple's senior director of system software, Brian Croll, said the performance improvements are the result of a new JavaScript engine called Nitro. Apple used the SunSpider benchmark to post the JavaScript results, and the iBench benchmark for the HTML numbers, he said.
Croll emphasised Safari 4's support for web standards such as HTML 5, which allows web applications to work while offline, and CSS 3 for adding graphical effects. Safari 4 has passed the Acid3 test developed by the Web Standards Project, while Firefox 3 and Internet Explorer 7 have yet to do so, he said.
In terms of changes that will be more visible to average users, Safari 4 moves the tabs from below the address bar to the very top of the window. It allows users to add a new tab by clicking a '+' sign in the upper right-hand corner of the window.
Apple also added the Cover Flow interface, which is now found in almost every piece of its software. This feature lets users scroll backwards through their browsing history as if they were flipping through album covers.
Apple added some new history-browsing options. It placed the Cover Flow interface in the basic history view, and added a new feature called Top Sites, which checks the various websites the user visits most frequently and arranges them in a grid pattern. If a Top Site has published new content since the last time it was visited, a white star on a blue background appears in the upper right-hand corner of the view for that site.
The Safari 4 test version also has a Smart Address Field feature, which is similar to Firefox's Smart Location 'awesome bar'.
Windows users will notice a new "Windows-native look", according to Croll, that uses the standard Windows font rendering. Safari has been available as a Windows browser since June 2007.
Safari is used by about eight percent of internet surfers, according to figures from Net Applications, which places it behind Internet Explorer and Firefox.
