<!DOCTYPE html>
<html>
<body>
<input type="datetime" id="myDatetime"><br><br>
<button onclick="disableBtn()">Disable Datetime Field</button>
<button onclick="undisableBtn()">Undisable Datetime Field</button>
<p><strong>Note:</strong> input elements with type="datetime" do not show as any datetime field/calendar in any of the major browsers, except Safari.</p>
<script>
function disableBtn() {
document.getElementById("myDatetime").disabled = true;
}
function undisableBtn() {
document.getElementById("myDatetime").disabled = false;
}
</script>
</body>
</html>