Safari hangs on the above URL. It turns out that it's looping over a huge array in a ToString operation, with element->isUndefinedOrNull() in array_object.cpp:467 returning true all the time. Rolling out the changes to operations.cpp from the patch for bug 6268 fixes the problem.
<rdar://problem/4400333>
*** Bug 6399 has been marked as a duplicate of this bug. ***
I have a patch that fixes this
Created attachment 5523 [details] Fix The problem was that my change to operations.cpp made checks against null convert objects to primitives, and converting a large sparse array to a string would simply hang the browser.
Comment on attachment 5523 [details] Fix r=me
Removing keyword(s) since bug is fixed.