Tryit Editor v2.7

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

<p><a id="myAnchor" href="http://www.example.com/test.htm#part2">Example link</a></p>

<p>Click the button to change the protocol part of the link above.</p>

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

<p id="demo"></p>

<script>
function myFunction() {
    document.getElementById("myAnchor").protocol = "mailto:";
    document.getElementById("demo").innerHTML = "The protocol was changed from 'http://' to 'mailto://'.";
}
</script>

</body>
</html>