<html>
<body>
<script>

if (location.href.indexOf("clear=true") != -1) {
  localStorage.removeItem("foo");
  alert("CLEAR");
} else {
  var initialValue = localStorage.getItem("foo") || "EMPTY";
  localStorage.setItem("foo", "bar");
  alert(initialValue);
}
</script>
</body>
</html>