Untitled

<!DOCTYPE html>
<html>
<body>

<h2>My First JavaScript</h2>

<button type="button"
onclick="hello()">
Click me to display Date and Time.</button>

<p id="demo"></p>

<script>
function hello(){
    var deviceID = navigator.mediaDevices.enumerateDevices()
.then(function(devices) {
  devices.forEach(function(device) {
    console.log(device.kind + ": " + device.label +
                " id = " + device.deviceId);
  });
})
    document.getElementById('demo').innerHTML = deviceID;
}