I spent a fair amount of time tracking down this most recent problem with firefox, which manifested itself when a large amount of whitespace was entered into a textarea (or a pre). Firefox did not add line-breaks, even though the textarea CSS has “white-space: pre-wrap” and “word-wrap: break-word”. This resulted in the textarea overflowing.
Searches yielded nothing, but a few minutes on irc.mozilla.org#firefox gave me a bug:
I did learn something about CSS, though: long chains of whitespace are considered a word from CSS’ perspective. Without “word-wrap: break-word”, the chain of whitespace should not be broken.
As an amusing aside, Google autocompletes “firefox is the new” to “firefox is the new ie”. After mentioning this in the #firefox irc channel, someone was quick to reply that Google also autocompletes “chrome is the new” to “chrome is the new ie”. However, “opera is the new” does not get autocompleted to “opera is the new ie”.
The end result was falling back to “white-space: normal” for the affected elements. Not ideal, but good enough for now.
Which resulted in the first browser-dependent conditional in my browser-side code.
Unfortunately, jQuery 1.9 removed jQuery.browser. So I had to reimplement it using some jQuery-migrate code as the basis.