I'm getting html5 validation errors on this as well when running my site through http://validator.w3.org.

Validation Output: 5 Errors (3 of which are metatag)

Error Line 9, Column 44: Bad value cleartype for attribute http-equiv on element meta.
<meta http-equiv="cleartype" content="on" />

Error Line 19, Column 47: Bad value MobileOptimized for attribute name on element meta: Keyword mobileoptimized is not registered.
<meta name="MobileOptimized" content="width" />

Error Line 20, Column 47: Bad value HandheldFriendly for attribute name on element meta: Keyword handheldfriendly is not registered.
<meta name="HandheldFriendly" content="true" />

Solved

By removing the information set in your theme > metatags tab the errors go away.

MobileOptimized, HandheldFriendly set to blank as in leave the boxes empty and uncheck if checked the " Enable Cleartype in IE Mobile devices"

The default is that MobileOptimized is set to width, HandheldFriendly to true.

Comments

Jeff Burnz’s picture

Jeff Burnz CreditAttribution: Jeff Burnz commented
Title: HTML5 validation errors » HTML5 metatag validation
Status: Active » Closed (works as designed)

I don't really see it as an error to include default settings that suit most sites, for most devices, even if the W3C validator objects.

The instructions to leave something "blank to omit" it are in the settings description, so it should be clear how to do this.

A more balanced post would include why these settings are there and what the implications are of omitting them.

kingfisher64’s picture

kingfisher64 CreditAttribution: kingfisher64 commented

I'm not sure Jeff what these settings do, being honest and don't have the time to properly research it at the moment to write a more balanced post.

I just thought incase someone else was struggling to find out how to fix the validation I'd post it here.