The profile attribute on the <head> tag is no longer supported either, and this
is something you see in a lot of WordPress templates.Finally, the longdesc attribute for <img> and <iframe> elements is gone, which
is a bit of a disappointment to accessibility advocates, because longdesc was
an accepted way of providing additional descriptive information to users of
screen readers.If you plan on using HTML5 with your existing sites, you’ll want to look for
these elements and remove them or replace them with more semantic ones.
Be sure to validate your pages with the W3C Validator service;^3 this will help
you locate deprecated tags and attributes.Competing Corporate Interests
Internet Explorer is not the only browser slowing adoption of HTML5 and
CSS3. Google, Apple, and the Mozilla Foundation have their own agendas,
as well, and they’re battling it out for supremacy. They’re arguing over video
and audio codec support, and they’re including their opinions in their
browser releases. For example, Safari will play MP3 audio with the <audio>
tag, but ogg files won’t work. Firefox, however, supports ogg files instead of
mp3 files.Eventually these differences will be resolved. In the meantime, we can make
smart choices about what we support, either by limiting what we implement
to the browsers our target audiences use or by implementing things multiple
times, once for each browser, until the standards are finalized. It’s not as
painful as it sounds. You’ll learn more about this in Chapter 7, Embedding
Audio and Video, on page 131.HTML5 and CSS3 Are Still Works in Progress
They’re not final specifications, and that means anything in those specifica-
tions could change. Although Firefox, Chrome, and Safari have strong HTML5
support, if the specification changes, the browsers will change with it, and
this could lead to some deprecated, broken websites. For example, over the
last few years CSS3 box shadows have been removed from and readded to
the specification, and the Web Sockets protocol has been modified, breaking
client-server communications entirely.If you follow the progress of HTML5 and CSS3 and stay up-to-date with what’s
happening, you’ll be fine. The HTML5 specification is at http://www.w3.org/TR/html5/.Chapter 1. An Overview of HTML5 and CSS3 • 8
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