HTML5 in Drupal
While there is an effort to make Drupal 8 HTML5-native, (see drupal.org/node/963832), the specification and its adoption were not ready for Drupal 7. However, there is a strong effort happening in the community to make Drupal ready for HTML5 right now.
http://definitivedrupal.org/ first edition page 940.
http://drupal.org/community-initiatives ... core/html5
Read more about the living HTML spec, HTML5 and CSS3 here: viewtopic.php?f=46&t=227
As an example the modernizr library can be integrated into your projects:
See also http://drupal.org/node/1019852