<!DOCTYPE html>
<meta charset="utf-8">
<title>Focus fixup rule one (no &lt;dialog>s involved)</title>
<link rel="author" title="Domenic Denicola" href="mailto:d@domenic.me">
<link rel="help" href="https://html.spec.whatwg.org/multipage/interaction.html#focus-fixup-rule">
<link rel="help" href="https://html.spec.whatwg.org/multipage/forms.html#attr-fieldset-disabled">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<div>
  <button id="button1">Button 1</button>
  <button id="button2">Button 2</button>
  <button id="button3">Button 3</button>
  <fieldset id="fieldset1"><button id="button4">Button 4</button></fieldset>
  <fieldset id="fieldset2" disabled><legend><button id="button5">Button 5</button></legend></fieldset>
  <div id="div" tabindex="0">Div</div>
  <div id="editable" contenteditable=true>editor</div>
</div>

<script>
"use strict";

test(() => {
  const button = document.querySelector("#button1");
  button.focus();

  assert_equals(document.activeElement, button, "Sanity check: the button must start focused");

  button.disabled = true;

  assert_not_equals(document.activeElement, button, "After disabling, the button must no longer be focused");
  assert_equals(document.activeElement, document.body, "After disabling, the body must be focused");

}, "Disabling the active element (making it inert)");

test(() => {
  const button = document.querySelector("#button2");
  button.focus();

  assert_equals(document.activeElement, button, "Sanity check: the button must start focused");

  button.hidden = true;

  assert_not_equals(document.activeElement, button, "After hiding, the button must no longer be focused");
  assert_equals(document.activeElement, document.body, "After hiding, the body must be focused");

}, "Hiding the active element");

test(() => {
  const button = document.querySelector("#button3");
  button.focus();

  assert_equals(document.activeElement, button, "Sanity check: the button must start focused");

  button.remove();

  assert_not_equals(document.activeElement, button, "After removing, the button must no longer be focused");
  assert_equals(document.activeElement, document.body, "After removing, the body must be focused");

}, "Removing the active element from the DOM");

test(() => {
  const fieldset = document.querySelector("#fieldset1");
  const button = document.querySelector("#button4");
  button.focus();
  assert_equals(document.activeElement, button, "Sanity check: the button must start focused");

  fieldset.disabled = true;

  assert_not_equals(document.activeElement, button, "After disabling ancestor fieldset, the button must no longer be focused");
  assert_equals(document.activeElement, document.body, "After disabling ancestor fieldset, the body must be focused");
}, "Disabling <fieldset> affects its descendants");

test(() => {
  const fieldset = document.querySelector("#fieldset2");
  const button = document.querySelector("#button5");
  button.focus();
  assert_equals(document.activeElement, button, "Sanity check: the button must start focused");

  fieldset.insertBefore(document.createElement("legend"), fieldset.firstChild);

  assert_not_equals(document.activeElement, button, "After changing a legend element, the button must no longer be focused");
  assert_equals(document.activeElement, document.body, "After changing a legend element, the body must be focused");
}, "Changing the first legend element in disabled <fieldset>");

test(() => {
  const div = document.querySelector("#div");
  div.focus();

  assert_equals(document.activeElement, div, "Sanity check: the div must start focused");

  div.removeAttribute("tabindex");

  assert_not_equals(document.activeElement, div, "After removing tabindex, the div must no longer be focused");
  assert_equals(document.activeElement, document.body, "After removing tabindex, the body must be focused");

}, "Removing the tabindex attribute from a div");

test(() => {
  const div = document.querySelector("#editable");
  div.focus();
  assert_equals(document.activeElement, div, "Sanity check: the div must start focused");

  div.contentEditable = false;

  assert_not_equals(document.activeElement, div, "After disabling contentEditable, the div must no longer be focused");
  assert_equals(document.activeElement, document.body, "After disabling contentEditable, the body must be focused");
}, "Disabling contenteditable");
</script>
