Firefox doesn't do simplistic string searches, for what it's worth. It actually tokenizes the HTML and kicks off loads from tokenization. If someone then misu

Firefox doesn't do simplistic string searches, for what it's worth. It actually tokenizes the HTML and kicks off loads from tokenization. If someone then misuses document.write the token stream has to be thrown out and things have to be retokenized, but that's rare in practice. The tradeoff is better accuracy of the preloader and not having to go through the text twice unless someone is misusing document.write.