Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<body>

<a id="myAnchor">A Link: Go to w3schools.com</a>

<p>Click the button to create a "class" attribute with the value "www.w3schools.com" and insert it to the a element above.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
    var anchor = document.getElementById("myAnchor");
    var att = document.createAttribute("href");
    att.value = "http://www.w3schools.com";
    anchor.setAttributeNode(att);
}
</script>

</body>
</html>