firefox-proof-focus-styles.js

/**
 *  ♫ Firefox-Proof Focus Styles ♫
 *  
 *  Define your focus styles this way: a.focus { outline: 2px solid hotpink; }
 *  Only mini-tiny-pico quirk is a slight delay before the focus style appears.
 *  
 *  https://gist.github.com/536465
 */

$('a').bind({
  keyup: function(e) {
    if (e.which == 9)
      $(this).addClass('focus')
  },
  blur: function() {
    $(this).removeClass('focus')
  }
})