It'll force to restart the parsing and reflow if the initial guess was wrong. Also while it works in practice it's an undecidable problem, you're just lucky the common character encodings work in a way that allows this faggotry to work. Typical WEB design quality. I chuckle when people ask for the "correct" way do to stuff in the HTML-and-friends cesspool. Just test in in the three of four browsers that matter or copy the code from a popular page so it's already tested for you.