Try it Yourself - JavaScript Reference audio

<!DOCTYPE html>
<html>
<body>

<p>Click the buttons to create an AUDIO element, one with preload set to "none", and one with preload set to "auto".</p>

<button onclick="myFunction('none')">Audio without preload</button>
<button onclick="myFunction('auto')">Audio with preload</button>
<br>

<script>
function myFunction(p) {
   var x = document.createElement("AUDIO");
   x.setAttribute("controls", "controls");

   var y = document.createElement("SOURCE");
   y.setAttribute("src", "horse.ogg");
   y.setAttribute("type", "audio/ogg");

   x.appendChild(y);
   var z = document.createElement("SOURCE");
   z.setAttribute("src", "horse.mp3");
   z.setAttribute("type", "audio/mpeg");
   x.appendChild(z);

   // Set the preload property:
   x.preload = p;

   document.body.appendChild(x);
}
</script>

</body>
</html>