Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<body>

Name: <input type="text" id="myText">

<p>Click the button to disable the text field.</p>

<button onclick="myFunction()">Disable Text field</button>

<script>
function myFunction() {
    document.getElementById("myText").disabled = true;
}
</script>

</body>
</html>