<!DOCTYPE html>
<html>
<body>
<form>
<fieldset id="myFieldset">
<legend>Personalia:</legend>
Name: <input type="text"><br>
Email: <input type="text"><br>
Date of birth: <input type="text">
</fieldset>
</form><br>
<button onclick="disableField()">Disable fieldset</button>
<button onclick="undisableField()">Undisable fieldset</button>
<script>
function disableField() {
document.getElementById("myFieldset").disabled = true;
}
function undisableField() {
document.getElementById("myFieldset").disabled = false;
}
</script>
</body>
</html>