<html>
<body>
<p id="demo">Click the button to get the value of the onclick attribute of the button element.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
var a=document.getElementsByTagName("BUTTON")[0];
var x=document.getElementById("demo");
x.innerHTML=a.attributes.getNamedItem("onclick").textContent;
}
</script>
<p><strong>Note:</strong> Internet Explorer 8 and earlier does not support the getNamedItem method.</p>
</body>
</html>