penders - 7:39 am on Sep 1, 2011 (gmt 0)

The first has a length of 4096, so I wonder if the browser is just chunking the data.

Interesting, FF has always had a 'problem' with a limit on the size of its TextNodes.
Sep 15, 2006 - problems when get nodeValue by Firefox . Help me plzz! [webmasterworld.com]
Jul 6, 2007 - Size limit of 4K for textarea in Moz/FF from xmlhttprequest? [webmasterworld.com]