title: Using server timestamp for filtering
body: <p>Firebase provides a mechanism to insert <a href="https://firebase.google.com/docs/database/web/offline-capabilities#section-latency" rel="nofollow">server timestamps</a>.</p>
  
  <p>I was wondering if it also can be used for filtering. Like this:</p>
  
  <pre><code>var db = firebase.database();
  var path = '/some/path';
  var ref = db.ref(path);
  ref.orderByChild('ts')
      .startAt(firebase.database.ServerValue.TIMESTAMP)
      .on('child_added', function(snap) {
          //do something
      });
  </code></pre>
  
  <blockquote>
    <p>Error: Query: First argument passed to startAt(), endAt(), or
    equalTo() cannot be an object.</p>
  </blockquote>