Set random value to many labels on load

<!DOCTYPE html>
<html>
<body>

<button onclick="this.innerHTML=Date()">The time is?</button>
<label onclick="this.innerHTML=Date()">ABC</label><br/>
<label>A</label><br/>
<label>A</label><br/>
<label>A</label><br/>
<label>A</label><br/>
<label>A</label><br/>
<p id="demo"></p>
<script>
    labels = document.getElementsByTagName("label");
    //alert(labels.length);
    for (var i=0; i< labels.length; i++) {
        labels[i].innerHTML =Math.floor( Math.random()*99);
    }
</script>
</body>
</html>