<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <title>Hello HTML5!</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body id="home">
    <!-- page menu -->
    <nav class="side-menu">Page Menu</nav>

    <!-- page content -->

    <p>Hello <span id="name">HTML5!</span></p>
    <input type="text" id="custom-name" placeholder="Insert your name">

    <script>
      var customNameInput = document.querySelector("input#custom-name"),
          nameElement = document.querySelector("#name");

      customNameInput.addEventListener("change", function(evt) {
        nameElement.textContent = evt.target.value;
      }, false);
    </script>
  </body>
</html>