<!DOCTYPE html>
<html>
<body>
<input type="number" id="myNumber" value="2">
<p>Click the button to set the number field to read-only.</p>
<p><strong>Tip:</strong> To see the effect, try to type something in the number field before and after clicking the button.</p>
<button onclick="myFunction()">Try it</button>
<p><strong>Note:</strong> input elements with type="number" are not supported in IE 9 and earlier versions.</p>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("myNumber").readOnly = true;
}
</script>
</body>
</html>