The Custom Classes plugin allows you to create custom classes for posts (when
post_class() is called) and for the
<body> class (when
body_class() is called). It creates a meta box on the edit post screen in the admin with two input boxes for adding your custom classes.
Custom post classes are added whenever your theme calls the
post_class() function, which is generally whenever a post is shown. Custom body classes are added on the single view of the post whenever your theme calls the