setuserid.html

<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
<script>
function getUrlParameters(){
  var url, hash, map, parts;
  url = window.location.href;
  hash = url.lastIndexOf('#');
  if (hash !== -1) {
    url = url.slice(0, hash);
  }
  map = {};
  parts = url.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m, key, value){
    return map[key] = decodeURIComponent(value).split('+').join(' ');
  });
  return map;
};

var url_params = getUrlParameters()
var userid = url_params.userid
if (userid) {
  localStorage.setItem('userid', userid)
}

</script>
</body>
</html>