I checked (http://validator.w3.org) my site to see if it's a valid HTML5 site and it's not. So I checked http://kaptinlin.com/themes/striking/ and there's also a lot of errors. Missing alt attributes (mostly for image_shadow.png), bad values in rel attributes, no space between attributes (height and alt framework\shortcodes\images.php), etc. We would have to change too many files in the Striking theme to fix it and the fixes will be overwritten after an update anyway so can you do something about it?
I found another thing. Sometimes WP (or Striking) inserts extra tag after the span which holds the image_shadow.png image. This causes "No p element in scope but a p end tag seen." error.
Update:
This seems to be a visual editor feature. Possible to fix with a couple of "Delete and Enter".
The tag issue to which michal referred was fixed in Ver 5.1.2. It was not noted in the changelog as the correction was just a space in a line of code. It was so trivial that we categorize it under misc fixes and don't generally note them.
In respect of html5 validation, I attached a couple of images from some validation checks we have done. The front page for example, checks out with no errors. The Blog page checks out with one error type, occurring in 4 instances.
In this case, it's the problem that wordpress has added the attribute "rel" to the link category and html5 needs the "rel" value to be registered, and wordpress has not yet done this.
So this is a matter of the right hand catching up with the left hand.
Nonetheless, we strive for clean code, and according to Themeforest, Striking passes with flying colors. Missing alt attributes are not an error, but a warning - but we shall go over these in the near future to catch any that are a potential source of concern. The next release of Striking shall have corrections to eliminate some warnings.
Happy Striking Websys Team James
1 - Markup Validation of http---kaptinlin.com-themes-striking- - W3C Markup Validator.jpg
1260 x 1466 - 229K
2 - Markup Validation of http---kaptinlin.com-themes-striking-blog- - W3C Markup Validator.jpg
Thanks for fixing this! I wonder if the image_shadow.png could be moved the background instead of being inserted using <img> tag. Obviously the alt tag for this image is (not very) important :-) It's just irritating a bit to see these validation warnings.
I see the rel attribute is a problem for many people using many variations of the lightbox script with HTML5. So this is not a strictly Striking problem. Thanks!