Toggle Div off and on

<button onclick="myFunction()">Click Me</button>

<div style="display:none;" id="myDIV">
This is my DIV element.
</div>

<script>
function myFunction() {
var x = document.getElementById("myDIV");
if (x.style.display === "none") {
x.style.display = "block";
} else {
x.style.display = "none";
}
}
</script>