<h2>MP subtest</h2> This form triggers a MP and gets filled in.<br> <form> Username: <input type="text" id="userfield" name="u"><br> Password: <input type="password" id="passfield" name="p"><br> <script> // Only notify when we fill in the password field. document.getElementById("passfield").addEventListener("input", function() { parent.postMessage("filled", "*"); }); </script> </form>