ARIA：按鈕角色

<div id="saveChanges" tabindex="0" role="button" aria-pressed="false">Save</div>

<button type="button" id="saveChanges">Save</button>

<div role="button"><h3>Title of my button</h3></div>

<div role="button"><h3 role="presentation">Title of my button</h3></div>

<div role="button">Title of my button</div>

<h1>ARIA Button Example</h1>
<ul id="nameList"></ul>
<label for="newName">Enter your Name: </label>
<input type="text" id="newName" />
<span
  role="button"
  tabindex="0"
  onclick="handleCommand(event)"
  onKeyDown="handleCommand(event)"
  >Add Name</span
>

[role="button"] {
  padding: 2px;
  background-color: navy;
  color: white;
  cursor: default;
}
[role="button"]:hover,
[role="button"]:focus,
[role="button"]:active {
  background-color: white;
  color: navy;
}
ul {
  list-style: none;
}

function handleCommand(event) {
  // Handles both mouse clicks and keyboard
  // activate with Enter or Space

  // Keypresses other then Enter and Space should not trigger a command
  if (
    event instanceof KeyboardEvent &&
    event.key !== "Enter" &&
    event.key !== " "
  ) {
    return;
  }

  // Get the new name value from the input element
  const newNameInput = document.getElementById("newName");
  const name = newNameInput.value;
  newNameInput.value = ""; // clear the text field
  newNameInput.focus(); // give the text field focus to enable entering and additional name.

  // Don't add blank entries to the list.
  if (name.length > 0) {
    const listItem = document.createElement("li");
    listItem.appendChild(document.createTextNode(name));

    // Add the new name to the list.
    const list = document.getElementById("nameList");
    list.appendChild(listItem);
  }
}

<button
  type="button"
  onclick="handleBtnClick(event)"
  onKeyDown="handleBtnKeyDown(event)">
  Mute Audio
</button>

<span
  role="button"
  tabindex="0"
  aria-pressed="false"
  onclick="handleBtnClick(event)"
  onKeyDown="handleBtnKeyDown(event)">
  Mute Audio
</span>

<audio
  id="audio"
  src="https://soundbible.com/mp3/Tyrannosaurus%20Rex%20Roar-SoundBible.com-807702404.mp3">
  Your browser does not support the `audio` element.
</audio>

button,
[role="button"] {
  padding: 3px;
  border: 2px solid transparent;
}

button:active,
button:focus,
[role="button"][aria-pressed="true"] {
  border: 2px solid #000;
}

function handleBtnClick(event) {
  toggleButton(event.target);
}

function handleBtnKeyDown(event) {
  // Check to see if space or enter were pressed
  // "Spacebar" for IE11 support
  if (event.key === " " || event.key === "Enter" || event.key === "Spacebar") {
    // Prevent the default action to stop scrolling when space is pressed
    event.preventDefault();
    toggleButton(event.target);
  }
}

function toggleButton(element) {
  const audio = document.getElementById("audio");

  // Check to see if the button is pressed
  const pressed = element.getAttribute("aria-pressed") === "true";

  // Change aria-pressed to the opposite state
  element.setAttribute("aria-pressed", !pressed);

  // Toggle the play state of the audio file
  if (pressed) {
    audio.pause();
  } else {
    audio.play();
  }
}