Web Developer Basics: Differences Between HTML4 And HTML5

“Now that we’ve seen how to use some of the newer whiz-bang
features of the draft HTML5 standard, it’s time to take a few steps
back and take a look at some of the other differences between HTML4
and HTML5.

“This article is intended to be a useful overview, not an
exhaustive reference, but remember that things are still and always
changing. The complete, up to date list of all the technical
differences may always be found on the W3C’s site. You also may
want to refer to this document for the actual details of the HTML5
specification itself.

“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.”

Complete
Story