StackOverflow 29213593

HTML

<script src="https://cdn.firebase.com/js/client/2.2.3/firebase.js"></script>

JavaScript

var ref = new Firebase('https://stackoverflow.firebaseio.com/29213593/');

function createSampleData() {
    var timestamp = Date.now();
    for (var i=0; i < 100; i++) {
        ref.push({ user: Math.round((Math.random() * 100)), timestamp: timestamp });
        timestamp = timestamp - 1000 - 10 * Math.round((Math.random() * 1000));
    }
}

createSampleData();

var startTime = 1427138419385,
    endTime = startTime + 60 * 1000;

ref
    .orderByChild('timestamp')
    .startAt(startTime)
    .endAt(endTime)
    .once('value', function(snap) {
       console.log('There are ', snap.numChildren(), ' messages in range', snap.val());
    });