Text - Introducing HTML5 - page 77

Features not covered in this topic
For completeness, here are some of the most interesting fea-
tures of HTML5 that, for reasons of page count or lack of imple-
mentation, aren't discussed further.
<embed>
Of course <embed> is well-known and has been used for years,
but was always an outlaw element that never validated. But like
that other outlaw, Robin Hood, it was widely supported because
it performed a useful function: It's the only way to get plugins
such as Flash to work reliably in all browsers, which explains
its overwhelmingly common usage (see 2008 stats at http://
dev.opera.com/articles/view/mama-plug-ins/ ) . Because of this,
there's no reason to keep it from validating. HTML5 paves that
particular cowpath and inally includes it into the formal lan-
guage speciication.
But hang on. Isn't HTML5 supposed to replace all these plugin-
based technologies? Contrary to the sensationalist headlines of
some journalists, HTML5 won't magically replace plugins over-
night, and now we can embed them into HTML5 without incur-
ring the wrath of the validator.
<keygen>
This element, which is already well supported in all browsers
other than the big IE elephant in the room, is used in situa-
tions where your form needs to send a public key. Take a look
at http://en.wikipedia.org/wiki/Public_key to learn more about
public-key cryptography.
And if you're still lost, you don't actually need this element!
<menu>, <command>
These are exciting elements that allow you to deine toolbars or
context menus for your application, with icons and associated
commands that execute scripts when activated. They're cooler
than a bucket full of Lou Reeds. However, no browser yet sup-
ports them, so we don't discuss them further.