const changeFavicon = link => { let $favicon = document.querySelector('link[rel="icon"]'); // If a <link rel="icon"> element already exists, // change its href to the given link. if ($favicon !== null) { $favicon.href = link; // Otherwise, create a new element and append it to <head>. } else { $favicon = document.createElement("link"); $favicon.rel = "icon"; $favicon.href = link; document.head.appendChild($favicon); } }; let icon = ''; // Photo Address changeFavicon (icon); // dynamically modify the site icon the let title = ''; // Website title document.title = title; // dynamically modify the site title