The new beta version 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.
Safari is used by about 8 percent of Internet surfers,, trailing Internet Explorer and FireFox.
Croll emphasized Safari 4's support for Web standards like 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.
As far as 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, and allows you to add a new tab by clicking a "+" sign in the uppermost right-hand corner of the window.
Apple added some new history browsing options, such as the aforementioned Cover Flow interface in the basic history view as well as a new feature called Top Sites, which checks the various Web sites you visit most frequently and arranges them in a grid pattern. If one of your Top Sites has published new content since the last time you visited, a white star on a blue background appears in the upper right-hand corner of the view for that site.
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.