When going to YouTube, it gives a embed code such as
<iframe title="YouTube video player"
class="youtube-player" type="text/html" width="640" height="385"
Note that the
is not valid html. There's no such attribute for iframe tag.
could anyone explain why google put that? I guess it's for some practical reason, but i couldn't guess what.
PS you can get the embed code by going here http://www.youtube.com/watch?v=QRvVzaQ6i8A
i also posted this question on
but i hoping some google employee would us some good insight.