Rails environment indicator

application.js

<% if Rails.env != 'production' %>
document.addEventListener("DOMContentLoaded", function() {
  $('body').append($('<div>').css({
    display: 'block',
    position: 'fixed',
    left: '20px',
    top: '500px',
    '-webkit-transform': 'rotate(-90deg)',
    '-moz-transform': 'rotate(-90deg)',
    '-o-transform': 'rotate(-90deg)',
    'font-size': '24px',
    'font-weight': 'bold',
    'width': '20px',
    'height': '20px'
  }).text(window.environment)
  );
});
<% end %>