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<!DOCTYPE html>
<html>
<body>
<form>
Password: <input type="password" id="myPsw">
</form>
<p>Write something in the password field, and then click the buttons to display and/or change the value.</p>
<button onclick="display()">Display value</button>
<button onclick="change()">Change value</button>
<script>
function display() {
  var x = document.getElementById("myPsw").value;
  alert("The value of the password field is: " + x);
}
function change() {
  var x = document.getElementById("myPsw").value = "NewPassword123";
  alert ("The value was changed to: " + x);
}
</script>
</body>
</html>