!!! 5
%html
  %head
    %title Testific.at - A/B testing for cats
    %link{rel: 'stylesheet', href: '/resource/style.css'}
    %link{rel: 'shortcut icon', href: '/resource/favicon.png'}
  %body
    = yield
    %script{src: '//cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js'}
    %script{src: '//cdnjs.cloudflare.com/ajax/libs/async/0.2.7/async.min.js'}
    %script{src: '/resource/script.js'}

!!! 5
%html{lang: 'en'}
  %head
    %title Testific.at - A/B testing for cats
    %link{rel: 'stylesheet', href: '/resource/style.css'}
    %link{rel: 'shortcut icon', href: '/resource/favicon.png'}
  %body
    = yield
    %script{src: '//cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js'}
    %script{src: '//cdnjs.cloudflare.com/ajax/libs/async/0.2.7/async.min.js'}
    %script{src: '/resource/script.js'}

Add lang attribute for correctness
Add lang attribute for correctness
