<!DOCTYPE html>
<html>
<body>
<button id="myBtn">My Button</button>
<br><br>
<button onclick="disableBtn()">Disable "My Button"</button>
<button onclick="undisableBtn()">Undisable "My Button"</button>
<script>
function disableBtn() {
document.getElementById("myBtn").disabled = true;
}
function undisableBtn() {
document.getElementById("myBtn").disabled = false;
}
</script>
</body>
</html>