<!DOCTYPE html>
<html>
<body>
<p>Click the button to find out if the button element has an onclick attribute.</p>
<button id="myBtn" onclick="myFunction()">Try it</button>
<p>Internet Explorer 8 and earlier does not support the hasAttribute() method.</p>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myBtn").hasAttribute("onclick");
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>