<!DOCTYPE html>
<html>
<body>

<p>This example uses the addEventListener() method to add two click events to the same button.</p>

<button id="myBtn">Try it</button>

<script>
var x = document.getElementById("myBtn");
x.addEventListener("click", myFunction);
x.addEventListener("click", someOtherFunction);

function myFunction() {
    alert ("Hello World!")
}

function someOtherFunction() {
    alert ("This function was also executed!")
}
</script>

</body>
</html>