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  1. 7 User interaction
    1. 7.1 The hidden attribute
    2. 7.2 Activation
    3. 7.3 Focus
      1. 7.3.1 Sequential focus navigation and the tabindex attribute
      2. 7.3.3 Document-level focus APIs
      3. 7.3.4 Element-level focus APIs
    4. 7.4 Assigning keyboard shortcuts
      1. 7.4.1 Introduction
      2. 7.4.2 The accesskey attribute
    5. 7.5 The contenteditable attribute
      1. 7.5.2 Making entire documents editable
    6. 7.6 Spelling and grammar checking

7 User interaction

7.1 The hidden attribute

All HTML elements may have the hidden content attribute set. The hidden attribute is a boolean attribute. When specified on an element, it indicates that the element is not yet, or is no longer, relevant.

In the following skeletal example, the attribute is used to hide the Web game's main screen until the user logs in:

  <h1>The Example Game</h1>
  <section id="login">
   <h2>Login</h2>
   <form>
    ...
    <!-- calls login() once the user's credentials have been checked -->
   </form>
   <script>
    function login() {
      // switch screens
      document.getElementById('login').hidden = true;
      document.getElementById('game').hidden = false;
    }
   </script>
  </section>
  <section id="game" hidden>
   ...
  </section>

The hidden attribute must not be used to hide content that could legitimately be shown in another presentation. For example, it is incorrect to use hidden to hide panels in a tabbed dialog, because the tabbed interface is merely a kind of overflow presentation — one could equally well just show all the form controls in one big page with a scrollbar. It is similarly incorrect to use this attribute to hide content just from one presentation — if something is marked hidden, it is hidden from all presentations, including, for instance, screen readers.

Elements that are not hidden should not link to or refer to elements that are hidden.

For example, it would be incorrect to use the href attribute to link to a section marked with the hidden attribute. If the content is not applicable or relevant, then there is no reason to link to it.

It would similarly be incorrect to use the ARIA aria-describedby attribute to refer to descriptions that are themselves hidden. Hiding a section means that it is not applicable or relevant to anyone at the current time, so clearly it cannot be a valid description of content the user can interact with.

Elements in a section hidden by the hidden attribute are still active, e.g. scripts and form controls in such sections still execute and submit respectively. Only their presentation to the user changes.

The hidden IDL attribute must reflect the content attribute of the same name.

7.2 Activation

element . click()

Acts as if the element was clicked.

7.3 Focus

7.3.1 Sequential focus navigation and the tabindex attribute

The tabindex content attribute specifies whether the element is focusable, whether it can be reached using sequential focus navigation, and the relative order of the element for the purposes of sequential focus navigation. The name "tab index" comes from the common use of the "tab" key to navigate through the focusable elements. The term "tabbing" refers to moving forward through the focusable elements that can be reached using sequential focus navigation.

The tabindex attribute, if specified, must have a value that is a valid integer.

The tabIndex IDL attribute must reflect the value of the tabindex content attribute. Its default value is 0 for elements that are focusable and −1 for elements that are not focusable.

7.3.2 Document-level focus APIs

document . activeElement

Returns the currently focused element.

document . hasFocus()

Returns true if the document has focus; otherwise, returns false.

window . focus()

Focuses the window. Use of this method is discouraged. Allow the user to control window focus instead.

window . blur()

Unfocuses the window. Use of this method is discouraged. Allow the user to control window focus instead.

7.3.3 Element-level focus APIs

element . focus()

Focuses the element.

element . blur()

Unfocuses the element. Use of this method is discouraged. Focus another element instead.

Do not use this method to hide the focus ring if you find the focus ring unsightly. Instead, use a CSS rule to override the 'outline' property.

For example, to hide the outline from links, you could use:

:link:focus, :visited:focus { outline: none; }

7.4 Assigning keyboard shortcuts

7.4.1 Introduction

Each element that can be activated or focused can be assigned a single key combination to activate it, using the accesskey attribute.

The exact shortcut is determined by the user agent, based on information about the user's keyboard, what keyboard shortcuts already exist on the platform, and what other shortcuts have been specified on the page, using the information provided in the accesskey attribute as a guide.

In order to ensure that a relevant keyboard shortcut is available on a wide variety of input devices, the author can provide a number of alternatives in the accesskey attribute.

Each alternative consists of a single character, such as a letter or digit.

User agents can provide users with a list of the keyboard shortcuts, but authors are encouraged to do so also. The accessKeyLabel IDL attribute returns a string representing the actual key combination assigned by the user agent.

7.4.2 The accesskey attribute

All HTML elements may have the accesskey content attribute set. The accesskey attribute's value is used by the user agent as a guide for creating a keyboard shortcut that activates or focuses the element.

If specified, the value must be an ordered set of unique space-separated tokens that are case-sensitive, each of which must be exactly one Unicode code point in length.

In the following example, a variety of links are given with access keys so that keyboard users familiar with the site can more quickly navigate to the relevant pages:

<nav>
 <p>
  <a title="Consortium Activities" accesskey="A" href="/Consortium/activities">Activities</a> |
  <a title="Technical Reports and Recommendations" accesskey="T" href="/TR/">Technical Reports</a> |
  <a title="Alphabetical Site Index" accesskey="S" href="/Consortium/siteindex">Site Index</a> |
  <a title="About This Site" accesskey="B" href="/Consortium/">About Consortium</a> |
  <a title="Contact Consortium" accesskey="C" href="/Consortium/contact">Contact</a>
 </p>
</nav>

In the following example, the search field is given two possible access keys, "s" and "0" (in that order). A user agent on a device with a full keyboard might pick Ctrl+Alt+S as the shortcut key, while a user agent on a small device with just a numeric keypad might pick just the plain unadorned key 0:

<form action="/search">
 <label>Search: <input type="search" name="q" accesskey="s 0"></label>
 <input type="submit">
</form>

In the following example, a button has possible access keys described. A script then tries to update the button's label to advertise the key combination the user agent selected.

<input type=submit accesskey="N @ 1" value="Compose">
...
<script>
 function labelButton(button) {
   if (button.accessKeyLabel)
     button.value += ' (' + button.accessKeyLabel + ')';
 }
 var inputs = document.getElementsByTagName('input');
 for (var i = 0; i < inputs.length; i += 1) {
   if (inputs[i].type == "submit")
     labelButton(inputs[i]);
 }
</script>

On one user agent, the button's label might become "Compose (⌘N)". On another, it might become "Compose (Alt+⇧+1)". If the user agent doesn't assign a key, it will be just "Compose". The exact string depends on what the assigned access key is, and on how the user agent represents that key combination.

The accessKey IDL attribute must reflect the accesskey content attribute.

7.5 The contenteditable attribute

The contenteditable attribute is an enumerated attribute whose keywords are the empty string, true, and false. The empty string and the true keyword map to the true state. The false keyword maps to the false state. In addition, there is a third state, the inherit state, which is the missing value default (and the invalid value default).

The true state indicates that the element is editable. The inherit state indicates that the element is editable if its parent is. The false state indicates that the element is not editable.

element . contentEditable [ = value ]

Returns "true", "false", or "inherit", based on the state of the contenteditable attribute.

Can be set, to change that state.

Throws a SYNTAX_ERR exception if the new value isn't one of those strings.

element . isContentEditable

Returns true if the element is editable; otherwise, returns false.

7.5.1 Making entire documents editable

document . designMode [ = value ]

Returns "on" if the document is editable, and "off" if it isn't.

Can be set, to change the document's current state.

7.6 Spelling and grammar checking

The spellcheck attribute is an enumerated attribute whose keywords are the empty string, true and false. The empty string and the true keyword map to the true state. The false keyword maps to the false state. In addition, there is a third state, the default state, which is the missing value default (and the invalid value default).

The true state indicates that the element is to have its spelling and grammar checked. The default state indicates that the element is to act according to a default behavior, possibly based on the parent element's own spellcheck state. The false state indicates that the element is not to be checked.

element . spellcheck [ = value ]

Returns true if the element is to have its spelling and grammar checked; otherwise, returns false.

Can be set, to override the default and set the spellcheck content attribute.

This specification does not define the user interface for spelling and grammar checkers. A user agent could offer on-demand checking, could perform continuous checking while the checking is enabled, or could use other interfaces.