<!DOCTYPE html>
<html>
<body>
Month:
<input type="month" id="myMonth" min="2014-04" max="2014-09">
<p>Click the button to change the value of the min attribute of the month field.</p>
<button onclick="myFunction()">Try it</button>
<p><strong>Note:</strong> input elements with type="month" do not show as any date field/calendar in Firefox.</p>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myMonth").min= "2014-01";
document.getElementById("demo").innerHTML = "The value of the min attribute was changed from '2014-04' to '2014-01'.";
}
</script>
</body>
</html>