How do I add an "Add to Favorites" button or link on my website?

jQuery Version

$(function() {
  $('#bookmarkme').click(function() {
    if (window.sidebar && window.sidebar.addPanel) { // Mozilla Firefox Bookmark
      window.sidebar.addPanel(document.title, window.location.href, '');
    } else if (window.external && ('AddFavorite' in window.external)) { // IE Favorite
      window.external.AddFavorite(location.href, document.title);
    } else if (window.opera && window.print) { // Opera Hotlist
      this.title = document.title;
      return true;
    } else { // webkit - safari/chrome
      alert('Press ' + (navigator.userAgent.toLowerCase().indexOf('mac') != -1 ? 'Command/Cmd' : 'CTRL') + ' + D to bookmark this page.');
    }
  });
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<a id="bookmarkme" href="#" rel="sidebar" title="bookmark this page">Bookmark This Page</a>

This code is the corrected version of iambriansreed's answer:

<script type="text/javascript">
    $(function() {
        $("#bookmarkme").click(function() {
            // Mozilla Firefox Bookmark
            if ('sidebar' in window && 'addPanel' in window.sidebar) { 
                window.sidebar.addPanel(location.href,document.title,"");
            } else if( /*@cc_on!@*/false) { // IE Favorite
                window.external.AddFavorite(location.href,document.title); 
            } else { // webkit - safari/chrome
                alert('Press ' + (navigator.userAgent.toLowerCase().indexOf('mac') != - 1 ? 'Command/Cmd' : 'CTRL') + ' + D to bookmark this page.');
            }
        });
    });
</script>