function displayHeader() { const links = [ { href: "/", name: "Home", accessKey: "h", }, { href: "/register/", name: "Register", accessKey: "r", }, { href: "/login/", name: "Login", accessKey: "l", }, { href: "/upload/", name: "Upload", accessKey: "u", }, ].map(({name, href, accessKey}) => { if (href === window.location.pathname) { return `<a href="${href}" accesskey="${accessKey}"><b>${name}</b></a>` } else { return `<a href="${href}" accesskey="${accessKey}">${name}</a>` } }).join(" - "); document.querySelector("h1").outerHTML = ` <header> <a href="/"> <h1 id="app-name">MaoTube</h1> </a> <nav> ${links} </nav> <form method="GET" target="_self" action="/search"> <input type="text" id="search" name="query" placeholder="Search"> <input type="submit" value="Search"> </form> </header> ` } displayHeader();