Untitled

<!DOCTYPE html>
<html>
<body>

 <h1 style="margin: 100px">get user media time test</h1>
 <div width="300px" height="300px" style="margin: 100px">
  <button id="btn" style="height:100px; width:250px; font-size:25px;">call getUserMedia</button>
 </div>

 <script>
    var btn = document.getElementById("btn");
    btn.onclick = myFunction;

    function myFunction() {
    var time1 = new Date().getTime();
    console.log("Before" + time1);
    navigator.mediaDevices.getUserMedia({ video:false ,audio: true})
        .then(function(stream) {
        var time2 = new Date().getTime();
        console.log("after" + time2);
        var diff = time2-time1;
        alert(diff)
        })
        .catch(function(err) {
        console.log('Error gettingUserMedia: %s', err);
        });
    }
 </script>

</body>
</html>