energylink/public/app/core/utils/outline.js

// outline.js
// based on http://www.paciellogroup.com/blog/2012/04/how-to-remove-css-outlines-in-an-accessible-manner/
(function(d) {
  "use strict";

  var style_element = d.createElement('STYLE'),
    dom_events = 'addEventListener' in d,
    add_event_listener = function(type, callback) {
      // Basic cross-browser event handling
      if(dom_events){
        d.addEventListener(type, callback);
      } else {
        d.attachEvent('on' + type, callback);
      }
    },
    set_css = function(css_text) {
      // Handle setting of <style> element contents in IE8
      !!style_element.styleSheet ? style_element.styleSheet.cssText = css_text : style_element.innerHTML = css_text;
    };

  d.getElementsByTagName('HEAD')[0].appendChild(style_element);

  // Using mousedown instead of mouseover, so that previously focused elements don't lose focus ring on mouse move
  add_event_listener('mousedown', function() {
    set_css(':focus{outline:0 !important}::-moz-focus-inner{border:0;}');
  });

  add_event_listener('keydown', function() {
    set_css('');
  });

})(document);