How To Add A Cross-Browser, Add-To-Favorites Bookmark Button

add.to.bookmarks.button.js

jQuery(document).ready(function($) {
  $('#bookmark-this').click(function(e) {
    var bookmarkURL = window.location.href;
    var bookmarkTitle = document.title;

    if ('addToHomescreen' in window && window.addToHomescreen.isCompatible) {
      // Mobile browsers
      addToHomescreen({ autostart: false, startDelay: 0 }).show(true);
    } else if (window.sidebar && window.sidebar.addPanel) {
      // Firefox version < 23
      window.sidebar.addPanel(bookmarkTitle, bookmarkURL, '');
    } else if ((window.sidebar && /Firefox/i.test(navigator.userAgent)) || (window.opera && window.print)) {
      // Firefox version >= 23 and Opera Hotlist
      $(this).attr({
        href: bookmarkURL,
        title: bookmarkTitle,
        rel: 'sidebar'
      }).off(e);
      return true;
    } else if (window.external && ('AddFavorite' in window.external)) {
      // IE Favorite
      window.external.AddFavorite(bookmarkURL, bookmarkTitle);
    } else {
      // Other browsers (mainly WebKit - Chrome/Safari)
      alert('Press ' + (/Mac/i.test(navigator.userAgent) ? 'Cmd' : 'Ctrl') + '+D to bookmark this page.');
    }

    return false;
  });
});

// from https://www.thewebflash.com/how-to-add-a-cross-browser-add-to-favorites-bookmark-button-to-your-website/