distance.html

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title>distance</title>
  </head>
  <body>
    <span style="font-size: 30px;" id = "distance"></span>
  </body>
  <script src="https://www.gstatic.com/firebasejs/5.8.0/firebase.js"></script>
  <script src="js/firebaseInit.js"></script>
  <script src="js/distance.js" type="text/javascript">
  </script>
</html>