<!DOCTYPE html>
<html>
<body>
<p id="p1">Hello World!</p>
<script id="myScript" src="demo_async.js" async></script>
<p>Click the button to find out if the script was executed asynchronously as soon as it was available.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myScript").async;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>