<!DOCTYPE html>
<html>
<body>
<form action="demo_keygen.asp" method="get">
Username: <input type="text" name="usr_name">
Encryption: <keygen id="myKeygen" name="security">
<input type="submit">
</form><br>
<button onclick="disableKey()">Disable Keygen field</button>
<button onclick="undisableKey()">Undisable Keygen field</button>
<script>
function disableKey() {
document.getElementById("myKeygen").disabled = true;
}
function undisableKey() {
document.getElementById("myKeygen").disabled = false;
}
</script>
</body>
</html>