<!DOCTYPE html>
<html>
<body>
<input type="month" id="myMonth"><br><br>
<button onclick="disableBtn()">Disable Month Field</button>
<button onclick="undisableBtn()">Undisable Month Field</button>
<p><strong>Note:</strong> input elements with type="month" are not supported in Internet Explorer or Firefox.</p>
<script>
function disableBtn() {
document.getElementById("myMonth").disabled = true;
}
function undisableBtn() {
document.getElementById("myMonth").disabled = false;
}
</script>
</body>
</html>