Differences with HTML 4 and HTML 5

[maxsamuel]

The first thing you should know is that, perhaps for the first time, the development of a language standard is acknowledging the real world. In order to keep file compatibility with the current standard - which is technically HTML 4.01 - the brave decision was made to separate the way the web browser renders files from the way we, as developers, must write them. So the browser, or "user agent", must still process HTML4 constructs like the center element, because there will still be millions of files on the Internet that happen to use it. But we won't be writing any more HTML with center; it's simply being dropped from the language (use CSS instead). This compatibility goes both ways: older browsers can (and will) simply ignore HTML5 code without screwing things up.