add_bookmark.js

$(document).ready(() => {
  $("#add_bookmark").click(() => {
    // Mozilla Firefox Bookmark
    window.sidebar && window.sidebar.addPanel(location.href, document.title,"");
    // IE Favorite
    window.external && window.external.AddFavorite(location.href, document.title); 
    // Opera Hotlist
    if( window.opera && window.print ) { 
      this.title=document.title;
      return true;
    }
  });
});

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

//second version
$(".js-bookmark").click(() =>  {
	// Firefox <23
	window.sidebar && window.sidebar.addPanel && window.sidebar.addPanel(document.title,window.location.href,'');
  // Internet Explorer
	window.external && ('AddFavorite' in window.external) && window.external.AddFavorite(location.href,document.title); 
  // Opera <15 and Firefox >23
	if( window.opera && window.print || window.sidebar && ! (window.sidebar instanceof Node) ) { 
		/**
		 * For Firefox <23 and Opera <15, no need for JS to add to bookmarks
		 * The only thing needed is a `title` and a `rel="sidebar"`
		 * To ensure that the bookmarked URL doesn't have a complementary `#` from our trigger's href
		 * we force the current URL
		 */
		triggerBookmark.attr('rel', 'sidebar').attr('title', document.title).attr('href', window.location.href);
		return true;
	
	} else { // For the other browsers (mainly WebKit) we use a simple alert to inform users that they can add to bookmarks with ctrl+D/cmd+D
		
		alert('You can add this page to your bookmarks by pressing ' + (navigator.userAgent.toLowerCase().indexOf('mac') != - 1 ? 'Command/Cmd' : 'CTRL') + ' + D on your keyboard.');
	
	}
	// If you have something in the `href` of your trigger
	return false;
});