http://www.macnn.com/articles/11/11/29/allows.pdfs.to.be.displayed.within.web.content/
Apple updates Safari to v5.1.2 for Mac, Windows
updated 07:30 pm EST, Tue November 29, 2011
Allows PDFs to be displayed within web content
Apple has released Safari 5.1.2, a bugfix release that contains several improvements, including addressing issues that can cause some webpages to flash white and other issues that would cause hangs and memory leaks. The new version improves stability and allows PDFs to be displayed within web content. The update is available for Lion (10.7.2), Snow Leopard (10.6.8) and Windows XP SP2 or later.
The Windows version of the download also includes a QuickTime setup file. The Lion version is a 38.7MB file, the Snow Leopard version comes in at 47.1MB, and the Windows version is 36.5MB with the optional 54.9MB QuickTime setup file.
Fresh-Faced Recruit
Joined: Jul 2003
Seeing things
I thought that white flash was just my machine behaving badly.