Javascript to add a bookmark - Cross Browser

bookmark.js

/**
 *
 * Add to bookmark
 * Several tests are necessary in order for this "simple" action to work in most of the browsers
 *
 */

// First, we define the element where the "Add to bookmark" action will trigger
var triggerBookmark = $(".js-bookmark"); // It must be an `a` tag

triggerBookmark.click(function() {
	
	if (window.sidebar && window.sidebar.addPanel) { // Firefox <23
		
		window.sidebar.addPanel(document.title,window.location.href,'');

	} else if(window.external && ('AddFavorite' in window.external)) { // Internet Explorer

		window.external.AddFavorite(location.href,document.title); 

	} else if(window.opera && window.print || window.sidebar && ! (window.sidebar instanceof Node)) { // Opera <15 and Firefox >23
		/**
		 * 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;
});

waist of time

What an hourglass! ⌛

legendary, thx @nazywamsiepawel