It would seem that the Safari browser is not particularly keen on innerHTML property of document.body and on large document will always cause the browser to crash. This is something that I've came across while debugging FUDforum search term highlighting code that was using JavaScript code that would perform the highlighting and then replace the entire body via
CODE:
document.body.innerHTML = newBody;
While an annoying bug it cannot be blamed entirely on Safari developers, first of all innerHTML is not part of the specification offered by W3C, so technically speaking Safari does not even have to support it. That said it is supported by IE,Firefox and Opera, the latter two had no problem with the search highlight code either. IE, well IE being IE and worked 50% of the time. Furthermore changing the entire document body in one go is not the best of ideas and as Rasmus put it "Replacing the body is just wrong, you deserve what you get if you crash".
All this said it should be noted that in most other situations innerHTML works just fine in Safari and even the document.body.innerHTML can work, but only on simple documents, so be careful if you need to use it.