var options = { attributes: { rel: 'nofollow', title: 'Click for more information', }, className: 'internal-link', format: { url: function (value) { return value } }, ignoreTags: ['a'], validate: { url: function (value) { return value; } } }; var str = 'Underground Railroad--Routes of Fugitive Slaves to Canada'; document.write(linkifyHtml(str, options));