HTML

Living Standard — Last Updated 29 March 2023

1. 1. 6.11 The popover attribute
      1. 6.11.1 The popover target attributes
      2. 6.11.2 Popover light dismiss
      3. 6.11.3 The ToggleEvent interface

6.11 The popover attribute

All HTML elements may have the popover content attribute set. When specified, the element won't be rendered until it becomes shown, at which point it will be rendered on top of other page content.

<ul>
  <li>
    <a href=...>All Products</a>
    <button popovertarget=sub-nav>
     <img src=down-arrow.png alt="Product pages">
    </button>
    <ul popover id=sub-nav>
     <li><a href=...>Shirts</a>
     <li><a href=...>Shoes</a>
     <li><a href=...>Hats etc.</a>
    </ul>
  </li>
  <!-- other list items and links here -->
</ul>

When using popover on elements without accessibility semantics, for instance the div element, authors should use the appropriate ARIA attributes to ensure the popover is accessible.

<button popovertarget=menu aria-haspopup=menu>Actions</button>
 <div role=menu id=menu popover>
  <button role=menuitem tabindex=-1 autofocus>Edit</button>
  <button role=menuitem tabindex=-1>Hide</button>
  <button role=menuitem tabindex=-1>Delete</button>
</div>

<button id=submit>Submit</button>
<p><output><span popover=manual></span></output></p>

<script>
 const sBtn = document.getElementById('submit');
 const outSpan = document.querySelector('output [popover=manual]');
 let successMessage;
 let errorMessage;

 /* define logic for determining success of action
  and determining the appropriate success or error
  messages to use */

 sBtn.addEventListener('click', ()=> {
  if ( success ) {
   outSpan.textContent = successMessage;
  }
  else {
   outSpan.textContent = errorMessage;
  }
  outSpan.showPopover();

  setTimeout(function () {
   outSpan.hidePopover();
  }, 10000);
 });
<script>

Inserting a popover element into an output element will generally cause screen readers to announce the content when it becomes visible. Depending on the complexity or frequency of the content, this could be either useful or annoying to users of these assistive technologies. Keep this in mind when using the output element or other ARIA live regions to ensure the best user experience.

The popover attribute is an enumerated attribute with the following keywords and states:

The popover attribute's invalid value default is the manual state and its missing value default is the no popover state.

The popover IDL attribute must reflect the popover attribute, limited to only known values.

Every HTML element has a popover visibility state, initially hidden, with these potential values:

• hidden

• showing

The Document has an auto popover list, which is a list of all the elements in the Document's top layer whose popover attribute is in the auto state, in the same order.

The Document has a popover pointerdown target, which is an HTML element or null, initially null.

Every HTML element has a popover invoker, which is an HTML element or null, initially set to null.

Every HTML element has a popover toggle task, initially null, which is either null or a struct which has:

Task

A task which fires a ToggleEvent.

Old state

A string which represents the task's event's value for the oldState attribute.

The following attribute change steps are used for all HTML elements:

1. If namespace is not null, then return.

2. If localName is not popover, then return.

3. If oldValue and value are in different states, then run the hide popover algorithm given element, true, true, and false.

element.showPopover()

Shows the popover element by adding it to the top layer. If element's popover attribute is in the auto state, then this will also close all other auto popovers unless they are an ancestor of element according to the topmost popover ancestor algorithm.

element.hidePopover()

Hides the popover element by removing it from the top layer and applying display: none to it.

element.togglePopover()

If the popover element is not showing, then this method shows it. Otherwise, this method hides it.

The showPopover() method steps are:

1. Run show popover given this and true.

To show popover, given an HTML element element and a boolean throwExceptions:

1. If the result of running check popover validity given element, false, and throwExceptions is false, then return.

2. Assert: element is not in element's node document's top layer.

3. If the result of firing an event named beforetoggle, using ToggleEvent, with the cancelable attribute initialized to true, the oldState attribute initialized to "closed", and the newState attribute initialized to "open" at element is false, then return.

4. If the result of running check popover validity given element, false, and throwExceptions is false, then return.

   Check popover validity is called again because firing the beforetoggle event could have disconnected this element or changed its popover attribute.

5. Let document be element's node document.

6. Let shouldRestoreFocus be false.

7. If element's popover attribute is in the auto state, then:

   1. Let originalType be the value of element's popover attribute.

   2. Let ancestor be the result of running the topmost popover ancestor algorithm given element.

   3. If ancestor is null, then set ancestor to document.

   4. Run hide all popovers until given ancestor, false, and true.

   5. If originalType is not equal to the value of element's popover attribute, or if the result of running check popover validity given element, false, and throwExceptions is false, then return.

      Check popover validity is called again because running hide all popovers until above could have fired the beforetoggle event, and an event handler could have disconnected this element or called showPopover() on this element.

8. If the result of running topmost auto popover on document is null, then set shouldRestoreFocus to true.

   This ensures that focus is returned to the previously-focused element only for the first popover in a stack.

9. Set element's previously focused element to null.

10. Let originallyFocusedElement be document's focused area of the document's DOM anchor.

11. Add element to document's top layer.

12. Set element's popover visibility state to showing.

13. Run the popover focusing steps given element.

14. If shouldRestoreFocus is true and element's popover attribute is not in the no popover state, then set element's previously focused element to originallyFocusedElement.

15. Queue a popover toggle event task given element, "closed", and "open".

To queue a popover toggle event task given an element element, a string oldState, and a string newState:

1. If element's popover toggle task is not null, then:

   1. Set oldState to element's popover toggle task's old state.

   2. Remove element's popover toggle task's task from its task queue.

   3. Set element's popover toggle task to null.

2. Queue an element task given the user interaction task source and element to run the following steps:

   1. fire an event named toggle, using ToggleEvent, with the oldState attribute initialized to oldState, and the newState attribute initialized to newState at element.

   2. Set element's popover toggle task to null.

3. Set element's popover toggle task to a struct with task set to the just-queued task and old state set to oldState.

The hidePopover() method steps are:

1. Run the hide popover algorithm given this, true, true, and true.

To hide a popover given an HTML element element, a boolean focusPreviousElement, a boolean fireEvents, and a boolean throwExceptions:

1. If the result of running check popover validity given element, true, and throwExceptions is false, then return.

2. Let document be element's node document.

3. If element's popover attribute is in the auto state, then:

   1. Run hide all popovers until given element, focusPreviousElement, and fireEvents.

   2. If the result of running check popover validity given element, true, and throwExceptions is false, then return.

      Check popover validity is called again because running hide all popovers until could have disconnected element or changed its popover attribute.

   3. Assert: the last item in document's auto popover list is element.

4. Set element's popover invoker to null.

5. If fireEvents is true:

   1. Fire an event named beforetoggle, using ToggleEvent, with the oldState attribute initialized to "open", and the newState attribute initialized to "closed" at element.

   2. If the result of running check popover validity given element, true, and throwExceptions is false, then return.

      Check popover validity is called again because firing the beforetoggle event could have disconnected element or changed its popover attribute.

6. Remove element from the top layer.

7. Set element's popover visibility state to hidden.

8. If fireEvents is true, then queue a popover toggle event task given element, "open", and "closed".

9. Let previouslyFocusedElement be element's previously focused element.

10. If previouslyFocusedElement is not null, then:

    1. Set element's previously focused element to null.

    2. If focusPreviousElement is true, then run the focusing steps for previouslyFocusedElement; the viewport should not be scrolled by doing this step.

The togglePopover(force) method steps are:

1. If this's popover visibility state is showing, and force is not present or false, then run the hide popover algorithm given this, true, true, and true.

2. Otherwise, if force is not present or true, then run show popover given this and true.

To hide all popovers until, given an HTML element or Document endpoint, a boolean focusPreviousElement, and a boolean fireEvents:

1. Let document be endpoint's node document.

2. Let closeAllOpenPopovers be an algorithm which performs the following steps:

   1. Let popover be document's topmost auto popover.

   2. While popover is not null:

      1. Run the hide popover algorithm given popover, focusPreviousElement, fireEvents, and false.

      2. Set popover to document's topmost auto popover.

3. If endpoint is a Document, then run closeAllOpenPopovers and return.

4. Let lastToHide be null.

5. Let foundEndpoint be false.

6. For each popover in document's auto popover list:

   1. If popover is endpoint, then set foundEndpoint to true.

   2. Otherwise, if foundEndpoint is true, then set lastToHide to popover and break.

7. If foundEndpoint is false, then run closeAllOpenPopovers and return.

8. While lastToHide is not null and lastToHide's popover visibility state is showing and document's auto popover list is not empty:

   1. Run the hide popover algorithm given document's auto popover list's last element, focusPreviousElement, fireEvents, and false.

The hide all popovers until algorithm is used in several cases to hide all popovers that don't stay open when something happens. For example, during light-dismiss of a popover, this algorithm ensures that we close only the popovers that aren't related to the node clicked by the user.

To hide all popovers, given a Document document, run hide all popovers until given document, false, and false.

To find the topmost popover ancestor, given a Node newPopover, perform the following steps. They return an HTML element or null.

1. Let popoverPositions be an empty map.

2. Let index be 0.

3. Let document be newPopover's node document.

4. For each popover in document's auto popover list:

   1. Set popoverPositions[popover] to index.

   2. Increment index by 1.

5. Set popoverPositions[newPopover] to index.

6. Increment index by 1.

7. Let topmostPopoverAncestor be null.

8. Let checkAncestor be an algorithm which performs the following steps given candidate:

   1. If candidate is null, then return.

   2. Let candidateAncestor be the result of running nearest inclusive open popover given candidate.

   3. If candidateAncestor is null, then return.

   4. Let candidatePosition be popoverPositions[candidateAncestor].

   5. If topmostPopoverAncestor is null or popoverPositions[topmostPopoverAncestor] is less than candidatePosition, then set topmostPopoverAncestor to candidateAncestor.

9. Run checkAncestor given the result of running nearest inclusive open popover given newPopover's parent node within the flat tree.

10. For each button invoker that is a descendant of newPopover's root, in tree order:

    1. If invoker's popover target element is newPopover, then run checkAncestor given invoker.

11. return topmostPopoverAncestor.

To find the nearest inclusive open popover given a Node node, perform the following steps. They return an HTML element or null.

1. Let currentNode be node.

2. While currentNode is not null:

   1. If currentNode's popover attribute is in the auto state and currentNode's popover visibility state is showing, then return currentNode.

   2. Set currentNode to currentNode's parent in the flat tree.

3. Return null.

To find the topmost auto popover given a Document document, perform the following steps. They return an HTML element or null.

1. If document's auto popover list is not empty, then return document's auto popover list's last element.

2. Return null.

To perform the popover focusing steps for an HTML element subject:

1. Let control be the focus delegate of subject given "other" and true.

2. If control is null, then return.

3. Run the focusing steps given control.

4. Let topDocument be the active document of control's node document's browsing context's top-level browsing context.

5. If control's node document's origin is not the same as the origin of topDocument, then return.

6. Empty topDocument's autofocus candidates.

7. Set topDocument's autofocus processed flag to true.

To check popover validity for an HTML element element given a boolean expectedToBeShowing and a boolean throwExceptions, perform the following steps. They throw an exception or return a boolean.

1. If element's popover attribute is in the no popover state, then:

   1. If throwExceptions is true, then throw a "NotSupportedError" DOMException.

   2. Return false.

2. If one of the following conditions is true

   • element is not connected

   • expectedToBeShowing is true and element's popover visibility state is not showing

   • expectedToBeShowing is false and element's popover visibility state is not hidden

   • element is a dialog element and has an open attribute

   • element's fullscreen flag is set

   then:

   1. If throwExceptions is true, then throw a "InvalidStateError" DOMException.

   2. Return false.

3. Return true.

6.11.1 The popover target attributes

Buttons may have the following content attributes:

• popovertarget

• popovertargetaction

If specified, the popovertarget attribute value must be the ID of an element with a popover attribute in the same tree as the button with the popovertarget attribute.

The popovertargetaction attribute is an enumerated attribute with the following keywords and states:

The popovertargetaction attribute's invalid value default and missing value default are both the toggle state.

Whenever possible ensure the popover element is placed immediately after its triggering element in the DOM. Doing so will help ensure that the popover is exposed in a logical programmatic reading order for users of assistive technology, such as screen readers.

<button popovertarget="foo" popovertargetaction="show">
  Show a popover
</button>

<article popover=auto id="foo">
  This is a popover article!
  <button popovertarget="foo" popovertargetaction="close">Close</button>
</article>

<input type="button" popovertarget="foo" value="Toggle the popover">

<div popover=manual id="foo">
  This is a popover!
</div>

interface mixin PopoverInvokerElement {
  [CEReactions] attribute Element? popoverTargetElement;
  [CEReactions] attribute DOMString popoverTargetAction;
};

The popoverTargetElement IDL attribute must reflect the popovertarget attribute.

The popoverTargetAction IDL attribute must reflect the popovertargetaction attribute, limited to only known values.

To run the popover target attribute activation behavior given a Node node:

1. Let popover be node's popover target element.

2. If popover is null, then return.

3. If node's popovertargetaction attribute is in the show state and popover's popover visibility state is showing, then return.

4. If node's popovertargetaction attribute is in the hide state and popover's popover visibility state is hidden, then return.

5. If popover's popover visibility state is showing, then run the hide popover algorithm given popover, true, true, and false.

6. Otherwise, if popover's popover visibility state is hidden and the result of running check popover validity given popover, false, and false is true:

   1. Set popover's popover invoker to node.

   2. Run show popover given popover and false.

To get the popover target element given a Node node, perform the following steps. They return an HTML element or null.

1. If node is not a button, then return null.

2. If node is disabled, then return null.

3. If node has a form owner and node is a submit button, then return null.

4. Let popoverElement be node's popovertarget-associated element.

5. If popoverElement is null, then return null.

6. If popoverElement's popover attribute is in the no popover state, then return null.

7. Return popoverElement.

6.11.2 Popover light dismiss

"Light dismiss" means that pressing the Esc key or clicking outside of a popover whose popover attribute is in the auto state will close the popover.

Canceling popovers: when Document has a topmost auto popover showing, user agents may provide a user interface that, upon activation, queues an element task on the user interaction task source given topmost auto popover to run the hide popover algorithm given the topmost auto popover, true, true, and false.

To light dismiss open popovers, given an Event event:

1. Assert: event's isTrusted attribute is true.

2. Let target be event's target.

3. Let topmostPopover be the result of running topmost auto popover given target.

4. If topmostPopover is null, then return.

5. Let document be target's node document.

6. If event is a PointerEvent and event's type is pointerdown, then: set document's popover pointerdown target to the result of running topmost clicked popover given target.

7. If event is a PointerEvent and event's type is pointerup, then:

   1. Let ancestor be the result of running topmost clicked popover given target.

   2. Let sameTarget be true if ancestor is document's popover pointerdown target.

   3. Set document's popover pointerdown target to null.

   4. If ancestor is null, then set ancestor to document.

   5. If sameTarget is true, then run hide all popovers until given ancestor, false, and true.

Light dismiss open popovers will be called by the Pointer Events spec when the user clicks or touches anywhere on the page.

To find the topmost clicked popover, given a Node node:

1. Let clickedPopover be the result of running nearest inclusive open popover given node.

2. Let invokerPopover be the result of running nearest inclusive target popover for invoker given node.

3. Let getStackPosition be an algorithm which performs the following steps given an HTML element popover:

   1. Let popoverList be popover's node document's auto popover list.

   2. If popover is in popoverList, then return the index of popover in popoverList + 1.

   3. Return 0.

4. If the result of running getStackPosition given clickedPopover is greater than the result of running getStackPosition given invokerPopover, then return clickedPopover.

5. Return invokerPopover.

To find the nearest inclusive target popover for invoker given a Node node:

1. Let currentNode be node.

2. While currentNode is not null:

   1. Let targetPopover be currentNode's popover target element.

   2. If targetPopover is not null and targetPopover's popover attribute is in the auto state and targetPopover's popover visibility state is showing, then return targetPopover.

   3. Set currentNode to currentNode's ancestor in the flat tree.

6.11.3 The ToggleEvent interface

[Exposed=Window]
interface ToggleEvent : Event {
  constructor(DOMString type, optional ToggleEventInit eventInitDict = {});
  readonly attribute DOMString oldState;
  readonly attribute DOMString newState;
};

dictionary ToggleEventInit : EventInit {
  DOMString oldState = "";
  DOMString newState = "";
};

event.oldState

Set to "closed" when transitioning from closed to open, or set to "open" when transitioning from open to closed.

event.newState

Set to "open" when transitioning from closed to open, or set to "closed" when transitioning from open to closed.

The oldState attribute must return the value it was initialized to. It is initialized to "open" if the element with the popover attribute's popover visibility state is showing; otherwise "closed".

The newState attribute must return the value it was initialized to. It is initialized to "closed" if the element with the popover attribute's popover visibility state is showing; otherwise "open".