CodePen

HTML

            
              <a href="youtube.com/foo" data-href-domain="youtube.com">a link to youtube video</a>
            
          
!

↑ Insert the most common viewport meta tag

CSS

            
              a:after {
    content: " [" attr(data-href-domain) "]";
  }
            
          
!
? ?
? ?
Must be a valid URL.
+ add another resource
via CSS Lint

JS

            
              
            
          
!
Must be a valid URL.
+ add another resource
via JS Hint
Loading ..................