4.11. Interactive elements
4.11.1. The details
element
- Categories:
- Flow content.
- Sectioning root.
- Interactive content.
- Palpable content.
- Contexts in which this element can be used:
- Where flow content is expected.
- Content model:
- One
summary
element followed by flow content. - Tag omission in text/html:
- Neither tag is omissible
- Content attributes:
- Global attributes
open
- Whether the details are visible- Allowed ARIA role attribute values:
group
role (default - do not set)- Allowed ARIA state and property attributes:
- Global aria-* attributes
- Any
aria-*
attributes applicable to the default role. - DOM interface:
-
interface HTMLDetailsElement : HTMLElement { attribute boolean open; };
The details
element represents a disclosure widget from which the
user can obtain additional information or controls.
The details
element is not appropriate for footnotes. Please see §4.13.5 Footnotes for details on how to mark up footnotes.
If the details
element has a summary
child element, then the first summary child element represents the summary or legend of the details element. If there is no summary child
element, a user agent should provide its own legend (e.g. in English "Details"
or Spanish "Detalles").
The legend text should be presented in the language determined from the computed language of the element, if available, rather than from the locale of the browser/system.
The rest of the element’s contents represents the additional information or controls.
The open
content attribute is a boolean
attribute. If present, it indicates that both the summary and the additional information is
to be shown to the user. If the attribute is absent, only the summary is to be shown.
When the element is created, if the attribute is absent, the additional information should be hidden; if the attribute is present, that information should be shown. Subsequently, if the attribute is removed, then the information should be hidden; if the attribute is added, the information should be shown.
The user agent should allow the user to request that the additional information be shown or
hidden. To honor a request for the details to be shown, the user agent must set the open
attribute on the element to the empty string. To honor a request for the information to be hidden,
the user agent must remove the open
attribute from the element.
This ability to request that additional information be shown or hidden may simply be
the activation behavior of the appropriate summary
element, in the case such an element
exists. However, if no such element exists, user agents can still provide this ability through some
other user interface affordance.
Whenever the open
attribute is added to or removed from
a details
element, the user agent must queue a task that runs the
following steps, which are known as the details notification task steps, for this details
element:
-
If another task has been queued to run the details notification task steps for this
details
element, then abort these steps.When the
open
attribute is toggled several times in succession, these steps essentially get coalesced so that only one event is fired. - Fire a simple event named
toggle
at thedetails
element.
The task source for this task must be the DOM manipulation task source.
The open
IDL attribute must reflect the open
content attribute.
details
element being used to hide technical
details in a progress report.
<section class="progress window"> <h1>Copying "Really Achieving Your Childhood Dreams"</h1> <details> <summary>Copying... <progress max="375505392" value="97543282"></progress> 25%</summary> <dl> <dt>Transfer rate:</dt> <dd>452KB/s</dd> <dt>Local filename:</dt> <dd>/home/rpausch/raycd.m4v</dd> <dt>Remote filename:</dt> <dd>/var/www/lectures/raycd.m4v</dd> <dt>Duration:</dt> <dd>01:16:27</dd> <dt>Color profile:</dt> <dd>SD (6-1-6)</dd> <dt>Dimensions:</dt> <dd>320×240</dd> </dl> </details> </section>
details
element can be used to hide some controls by default:
<details> <summary><label for=fn>Name & Extension:</label></summary> <p><input type=text id=fn name=fn value="Pillar Magazine.pdf"> <p><label><input type=checkbox name=ext checked> Hide extension</label> </details>
One could use this in conjunction with other details
in a list to allow the user
to collapse a set of fields down to a small set of headings, with the ability to open each
one.
In these examples, the summary really just summarizes what the controls can change, and not the actual values, which is less than ideal.
open
attribute is added and removed
automatically as the user interacts with the control, it can be used in CSS to style the element
differently based on its state. Here, a stylesheet is used to animate the color of the summary
when the element is opened or closed:
<style> details > summary { transition: color 1s; color: black; } details[open] > summary { color: red; } </style> <details> <summary>Automated Status: Operational</summary> <p>Velocity: 12m/s</p> <p>Direction: North</p> </details>
4.11.2. The summary
element
- Categories:
- None.
- Contexts in which this element can be used:
- As the first child of a
details
element. - Content model:
- Either: phrasing content.
- Or: one element of heading content.
- Tag omission in text/html:
- Neither tag is omissible
- Content attributes:
- Global attributes
- Allowed ARIA role attribute values:
button
.- Allowed ARIA state and property attributes:
- Global aria-* attributes
- Any
aria-*
attributes applicable to the allowed roles. - DOM interface:
- Uses
HTMLElement
.
The first summary
child element of a details
element represents a summary, caption, or legend for the rest of the contents of the
parent details
element, if any.
The activation behavior of summary
elements is to run the following steps:
- If this
summary
element has no parent node, then abort these steps. - Let parent be this
summary
element’s parent node. - If parent is not a
details
element, then abort these steps. -
If the
open
attribute is present on parent, then remove it. Otherwise, set parent’sopen
attribute to the empty string.This will then run the details notification task steps.
4.11.3. The menu
element
- Categories:
- Flow content.
- Contexts in which this element can be used:
- Where flow content is expected.
- As the child of a
menu
element whosetype
attribute is in the context menu state. - Content model:
- If the element’s
type
attribute is in the context menu state: in any order, zero or moremenuitem
elements, zero or morehr
elements, zero or moremenu
elements whosetype
attributes are in the context menu state, and zero or more script-supporting elements. - Tag omission in text/html:
- Neither tag is omissible
- Content attributes:
- Global attributes
type
- Type of menu- Allowed ARIA role attribute values:
menu
(default - do not set).- Allowed ARIA state and property attributes:
- Global aria-* attributes
- Any
aria-*
attributes applicable to the default role. - DOM interface:
-
interface HTMLMenuElement : HTMLElement { attribute DOMString type; attribute DOMString label; };
The menu
element represents a group of commands.
The type
attribute is an enumerated
attribute indicating the kind of menu being declared. The attribute has one state. The
"context
" keyword maps to the context menu state, in which the element is declaring a context menu.
The missing value default is the null
.
If a menu
element’s type
attribute is in the context menu state, then the element represents commands for a context menu. The user can only examine and interact with the commands if that
context menu is activated.
The label
attribute gives the label of the
menu, to display nested menus in the UI: a context menu containing
another menu would use the nested menu’s label
attribute for
the submenu’s menu label. The label
attribute must only be
specified on menu
elements whose parent element is a menu
element.
A menu
is a currently relevant menu
element if it is the
child of a currently relevant menu
element, or if it is the designated pop-up menu of a button
element that is not inert, does not have a attribute, and is not
the descendant of an element with a
attribute.
A menu construct consists of an ordered list of zero or more menu item constructs, which can be any of:
- Commands, which can be marked as default commands (
menuitem
) - Separators (
hr
) - Other menu constructs, each with an associated submenu label, which allows the list to be nested (
menu
)
To build and show a menu for a particular menu
element source and with a particular element subject as a subject, the user agent
must run the following steps:
- Let pop-up menu be the menu construct created by the build a menu construct algorithm when passed the source element.
-
Display pop-up menu to the user, and let the algorithm that invoked this one continue.
If the user selects a menu item construct that corresponds to an element that still represents a command when the user selects it, then the user agent must invoke that command’s Action. If the command’s Action is defined as firing a
click
event, either directly or via the run synthetic click activation steps algorithm, then therelatedTarget
attribute of thatclick
event must be initialized to subject.Pop-up menus must not, while being shown, reflect changes in the DOM. The menu is constructed from the DOM before being shown, and is then immutable.
To build a menu construct for an element source, the user agent must run the following steps, which return a menu construct:
- Let generated menu be an empty menu construct.
-
Run the menu item generator steps for the
menu
element using generated menu as the output.The menu item generator steps for a
menu
element using a specific menu construct output as output are as follows: For each child node of themenu
in tree order, run the appropriate steps from the following list:- If the child is a
menuitem
element that defines a command - Append the command to output, respecting the command’s facets. If the
menuitem
element has adefault
attribute, mark the command as being a default command. - If the child is an
hr
element - Append a separator to output.
- If the child is a
menu
element with nolabel
attribute - Append a separator to output, then run
the menu item generator steps for this child
menu
element, using output as the output, then append another separator to output. - If the child is a
menu
element with alabel
attribute - Let submenu be the result of running the build a menu construct steps for the child
menu
element. Then, append submenu to output, using the value of the childmenu
element’slabel
attribute as the submenu label. - Otherwise
- Ignore the child node.
- If the child is a
- Remove from output any menu construct whose submenu label is the empty string.
- Remove from output any menu item construct representing a command whose Label is the empty string.
- Collapse all sequences of two or more adjacent separators in output to a single separator.
- If the first menu item construct in output is a separator, then remove it.
- If the last menu item construct in output is a separator, then remove it.
- Return output.
The type
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The label
IDL attribute must reflect the content attribute of the same name.
4.11.4. The menuitem
element
- Categories:
- None.
- Contexts in which this element can be used:
- As a child of a
menu
element whosetype
attribute is in the context menu state. - Content model:
- Text content.
- Tag omission in text/html:
- Neither tag is omissible
- Content attributes:
- Global attributes
type
- Type of commandlabel
- User-visible labelicon
- Icon for the commanddisabled
Whether the command or control is disableddefault
- Mark the command as being a default command- Also, the
title
attribute has special semantics on this element. - Allowed ARIA role attribute values:
menuitem
(default - do not set).- Allowed ARIA state and property attributes:
- Global aria-* attributes
- Any
aria-*
attributes applicable to the default role. - DOM interface:
-
interface HTMLMenuItemElement : HTMLElement { attribute DOMString type; attribute DOMString label; attribute DOMString icon; attribute boolean disabled; attribute boolean default; };
The menuitem
element represents a command that the user can invoke from a popup
menu (either a context menu or the menu of a menu button).
A menuitem
element with a label
attribute, or with text content defines a new command.
The type
attribute is an enumerated attribute with one keyword and state. The
"command
" keyword maps to the Command state.
The missing value default is the Command state.
- The Command state
- The element represents a normal command with an associated action.
The label
attribute can be used to give
the name of the command, as shown to the user. If the attribute is
specified, it must have a value that is not the empty string.
If the label
attribute is not present, and there is text content in the element,
that provides the name of the content as shown to the user.
The icon
attribute gives a picture that
represents the command. If the attribute is specified, the attribute’s value must contain a valid non-empty URL potentially surrounded by spaces. To obtain the absolute URL of
the icon when the attribute’s value is not the empty string, the attribute’s value must be parsed relative to the element’s node document. When the attribute is absent, or its
value is the empty string, or parsing its value fails, there is no icon.
The disabled
attribute is a boolean attribute that, if present, indicates that the command is not available in
the current state.
The distinction between disabled
and is subtle. A command would be disabled if, in the same
context, it could be enabled if only certain aspects of the situation were changed. A command
would be marked as hidden if, in that situation, the command will never be enabled. For example,
in the context menu for a water faucet, the command "open" might be disabled if the faucet is
already open, but the command "eat" would be marked hidden since the faucet could never be
eaten.
The title
attribute gives a hint describing
the command, which might be shown to the user to help him.
The default
attribute indicates, if
present, that the command is the one that would have been invoked if the user had directly
activated the menu’s subject instead of using the menu. The default
attribute is a boolean attribute.
The type
IDL attribute must reflect the content attribute of the same name, limited to only known
values.
The label
, icon
, disabled
, and default
IDL attributes must reflect the respective content attributes of the same name.
If the element’s Disabled State is false (enabled) then the element’s activation behavior is to do nothing.
Firing a synthetic click
event at the element
does not cause any of the actions described above to happen.
If the element’s Disabled State is true (disabled) then the element has no activation behavior.
The menuitem
element is not rendered except as part of a context menu.
<button contextmenu="editmenu">Commands...</button> <menu type="context" id="editmenu"> <menuitem label="Left" icon="icons/alL.png" onclick="setAlign('left')"> </menuitem> <menuitem label="Center" icon="icons/alC.png" onclick="setAlign('center')"> </menuitem> <menuitem label="Right" icon="icons/alR.png" onclick="setAlign('right')"> </menuitem> <hr> <menuitem disabled label="Publish" icon="icons/pub.png" onclick="publish()"> </menuitem> </menu>
4.11.5. Context menus
4.11.5.1. Declaring a context menu
The contextmenu
attribute gives the element’s
context menu. The value must be the ID of a menu
element in the same tree whose type
attribute is in the context menu state.
When a user right-clicks on an element with a contextmenu
attribute, the user agent will first fire a contextmenu
event at the element, and then, if that event is not
canceled, a show
event at the menu
element.
<form name="npc"> <label>Character name: <input name=char type=text contextmenu=namemenu required></label> <menu type=context id=namemenu> <menuitem label="Pick random name" onclick="document.forms.npc.elements.char.value = getRandomName()"> </menuitem> <menuitem label="Prefill other fields based on name" onclick="prefillFields(document.forms.npc.elements.char.value)"> </menuitem> </menu> </form>
This adds two items to the control’s context menu, one called "Pick random name", and one called "Prefill other fields based on name". They invoke scripts that are not shown in the example above.
4.11.5.2. Processing model
Each element has an assigned context menu, which can be null.
If an element A has a contextmenu
attribute, and there is
an element with the ID given by A’s contextmenu
attribute’s value in A’s tree, and the first such element in tree order is a menu
element, then A’s assigned context menu is that element.
Otherwise, if A has a parent element,
then A’s assigned context menu is the assigned context menu of its parent element.
Otherwise, A’s assigned context menu is null.
When an element’s context menu is requested (e.g., by the user right-clicking the element, or pressing a context menu key), the user agent must apply the appropriate rules from the following list:
- If the user requested a context menu using a pointing device
- The user agent must fire a trusted event with the name
contextmenu
, that bubbles and is cancelable, and that uses theMouseEvent
interface, at the element for which the menu was requested. The context information of the event must be initialized to the same values as the lastMouseEvent
user interaction event that was fired as part of the gesture that was interpreted as a request for the context menu. - Otherwise
- The user agent must fire a synthetic mouse
event named
contextmenu
that bubbles and is cancelable at the element for which the menu was requested.
Typically, therefore, the firing of the contextmenu
event will be the
default action of a mouseup
or keyup
event. The exact
sequence of events is user agent-dependent, as it will vary based on platform conventions.
The default action of the contextmenu
event depends on
whether or not the element for which the menu was requested has a non-null assigned context
menu when the event dispatch has completed, as follows.
If the assigned context menu of the element for which the menu was requested is null, the default action must be for the user agent to show its default context menu, if it has one.
Otherwise, let subject be the element for which the menu was requested, and let menu be the assigned context menu of target immediately after
the contextmenu
event’s dispatch has completed. The user
agent must fire a trusted event with the name show
at menu,
using the RelatedEvent
interface,
with the relatedTarget
attribute initialized
to subject. The event must be cancelable.
If this event (the show
event) is not canceled, then
the user agent must build and show the menu for menu with subject as the subject.
When it presents a context menu, the user agent should also provide access to its default context menu.
For example, it could merge the menu items from the two menus together,
provide the page’s context menu as a submenu of the default menu, or
handle right-clicks that have the Shift key depressed by showing the default context menu
instead of firing the contextmenu
event.
<img src="cats.jpeg" alt="Cats" contextmenu=catsmenu> <menu type="context" id="catsmenu"> <menuitem label="Pet the kittens" onclick="kittens.pet()"> <menuitem label="Cuddle with the kittens" onclick="kittens.cuddle()"> <menu label="Feed the kittens"> <menuitem label="Fish" onclick="kittens.feed(fish)"> <menuitem label="Chicken" onclick="kittens.feed(chicken)"> </menu> </menu>
When a user of a mouse-operated visual Web browser right-clicks on the image, the browser might pop up a context menu like this:
When the user clicks the disclosure triangle, such a user agent would expand the context menu in place, to show the browser’s own commands:
4.11.5.3. The RelatedEvent
interfaces
[Constructor(DOMString type, optional RelatedEventInit eventInitDict)] interface RelatedEvent : Event { readonly attribute EventTarget? relatedTarget; }; dictionary RelatedEventInit : EventInit { EventTarget? relatedTarget = null; };
- event .
relatedTarget
- Returns the other event target involved in this event. For example, when a
show
event fires on amenu
element, the other event target involved in the event would be the element for which the menu is being shown.
The relatedTarget
attribute must return the
value it was initialized to. It represents the other event target that is related to the event.
4.11.6. Commands
4.11.6.1. Facets
A command is the abstraction behind menu items, buttons, and links. Once a command is defined, other parts of the interface can refer to the same command, allowing many access points to a single feature to share facets such as the Disabled State.
Commands are defined to have the following facets:
- Label
-
The name of the command as seen by the user.
- Access Key
-
A key combination selected by the user agent that triggers the command. A command might not have an Access Key.
- Hidden State
-
Whether the command is hidden or not (basically, whether it should be shown in menus).
- Disabled State
-
Whether the command is relevant and can be triggered or not.
- Action
-
The actual effect that triggering the command will have. This could be a scripted event handler, a URL to which to navigate, or a form submission.
User agents may expose the commands that match the following criteria:
- The facet is false (visible)
- The element is in a
Document
that has an associated browsing context. - Neither the element nor any of its ancestors has a
attribute specified.
- The element is not a
menuitem
element, or it is a child of a currently relevantmenu
element, or it has an Access Key.
User agents are encouraged to do this especially for commands that have Access Keys, as a way to advertise those keys to the user.
For example, such commands could be listed in the user agent’s menu bar.
4.11.6.2. Using the a
element to define a command
An a
element with an href
attribute defines a command.
The Label of the command is the string given by the
element’s textContent
IDL attribute.
The Access Key of the command is the element’s assigned access key, if any.
The attribute, and false otherwise.
The Disabled State facet of the command is true if the element or one of its ancestors is inert, and false otherwise.
The Action of the command, if the element has a
defined activation behavior, is to run synthetic click activation steps on the element. Otherwise, it is just to fire a click
event at the element.
4.11.6.3. Using the button
element to define a command
A button
element always defines a command.
The Label, Access Key, , and Action facets of the command are determined as for a
elements (see the previous section).
The Disabled State of the command is true if the element or one of its ancestors is inert, or if the element’s disabled state is set, and false otherwise.
4.11.6.4. Using the input
element to define a command
An input
element whose type
attribute is in
one of the Submit Button
, Reset Button
, Image Button
, Button
, Radio Button
, or Checkbox
states defines a command.
The Label of the command is determined as follows:
- If the
type
attribute is in one of theSubmit Button
,Reset Button
,Image Button
, orButton
states, then the Label is the string given by thevalue
attribute, if any, and a user agent-dependent, locale-dependent value that the user agent uses to label the button itself if the attribute is absent. - Otherwise, if the element is a labeled control, then the Label is the string given by the
textContent
of the firstlabel
element in tree order whose labeled control is the element in question. (In DOM terms, this is the string given byelement.labels[0].textContent
.) - Otherwise, if the
value
attribute is present, then the Label is the value of that attribute. - Otherwise, the Label is the empty string.
The Access Key of the command is the element’s assigned access key, if any.
The attribute, and false otherwise.
The Disabled State of the command is true if the element or one of its ancestors is inert, or if the element’s disabled state is set, and false otherwise.
The Action of the command, if the element has a
defined activation behavior, is to run synthetic click activation steps on the element. Otherwise, it is just to fire a click
event at the element.
4.11.6.5. Using the option
element to define a command
An option
element with an ancestor select
element and either no value
attribute or a value
attribute that is not the empty string defines a command.
The Label of the command is the value of the option
element’s label
attribute, if there is
one, or else the value of option
element’s textContent
IDL attribute,
with leading and trailing white space
stripped, and with any sequences of two or more space
characters replaced by a single U+0020 SPACE character.
The Access Key of the command is the element’s assigned access key, if any.
The attribute, and false otherwise.
The Disabled State of the command is true if
the element is disabled, or if its nearest ancestor select
element is disabled, or if it or one
of its ancestors is inert, and false otherwise.
If the option
’s nearest ancestor select
element has a multiple
attribute, the Action of the command is to pick the option
element. Otherwise, the Action is to toggle the option
element.
4.11.6.6. Using the menuitem
element to define a
command
A menuitem
element always defines a command.
The Label of the command is the value of the element’s label
attribute, if there is one, or the empty string if
it doesn’t.
The Access Key of the command is the element’s assigned access key, if any.
The attribute, and false otherwise.
The Disabled State of the command is true if
the element or one of its ancestors is inert, or if the element has a disabled
attribute, and false otherwise.
The Action of the command, if the element has a
defined activation behavior, is to run synthetic click activation steps on the element. Otherwise, it is just to fire a click
event at the element.
4.11.6.7. Using the accesskey
attribute
on a label
element to define a command
A label
element that has an assigned access key and a labeled
control and whose labeled control defines a command, itself defines a command.
The Label of the command is the string given by the
element’s textContent
IDL attribute.
The Access Key of the command is the element’s assigned access key.
The Disabled State, and Action facets of the command are the same as the respective facets of the element’s labeled control.
,4.11.6.8. Using the accesskey
attribute
on a legend
element to define a command
A legend
element that has an assigned access key and is a child of a fieldset
element that has a descendant that is not a descendant of the legend
element and is neither a label
element nor a legend
element but that defines a command, itself defines a command.
The Label of the command is the string given by the
element’s textContent
IDL attribute.
The Access Key of the command is the element’s assigned access key.
The Disabled State, and Action facets of the command are the same as the respective
facets of the first element in tree order that is a descendant of the parent of the legend
element that defines a command but is not
a descendant of the legend
element and is neither a label
nor a legend
element.
4.11.6.9. Using the accesskey
attribute to define a command on other elements
An element that has an assigned access key defines a command.
If one of the earlier sections that define elements that define commands define that this element defines a command, then that section applies to this element, and this section does not. Otherwise, this section applies to that element.
The Label of the command depends on the element. If
the element is a labeled control, the textContent
of the first label
element in tree order whose labeled control is the
element in question is the Label (in DOM terms, this is
the string given by element.labels[0].textContent
). Otherwise,
the Label is the textContent
of the element
itself.
The Access Key of the command is the element’s assigned access key.
The attribute, and false otherwise.
The Disabled State of the command is true if the element or one of its ancestors is inert, and false otherwise.
The Action of the command is to run the following steps:
- Run the focusing steps for the element.
- If the element has a defined activation behavior, run synthetic click activation steps on the element.
- Otherwise, if the element does not have a defined activation behavior, fire a
click
event at the element.
4.11.7. The dialog
element
- Categories:
- Flow content.
- Sectioning root.
- Contexts in which this element can be used:
- Where flow content is expected.
- Content model:
- Flow content.
- Tag omission in text/html:
- Neither tag is omissible
- Content attributes:
- Global attributes
open
- Whether the dialog box is showing- Allowed ARIA role attribute values:
dialog
(default - do not set) oralertdialog
.- Allowed ARIA state and property attributes:
- Global aria-* attributes
- Any
aria-*
attributes applicable to the default or allowed roles. - DOM interface:
-
interface HTMLDialogElement : HTMLElement { attribute boolean open; attribute DOMString returnValue; void show(optional (MouseEvent or Element) anchor); void showModal(optional (MouseEvent or Element) anchor); void close(optional DOMString returnValue); };
The dialog
element represents a part of an application that a user interacts with
to perform a task, for example a dialog box, inspector, or window.
The open
attribute is a boolean
attribute. When specified, it indicates that the dialog
element is active and
that the user can interact with it.
The following is an example of a modal dialog
which provides a form for a user to add
coins to their wallet, as part of an online game.
... <body> <div> <!-- body content --> </div> <dialog> <h1>Add to Wallet</h1> <label for="num">How many gold coins do you want to add to your wallet?</label> <div><input name=amt id="num" type=number min=0 step=0.01 value=100></div> <p><strong>You add coins at your own risk.</strong></p> <div><label><input name=round type=checkbox> Only add perfectly round coins </label> <div><input type=button onclick="submit()" value="Add Coins"></div> </dialog> </body> ...
A dialog
element without an open
attribute
specified should not be shown to the user. This requirement may be implemented indirectly through
the style layer. For example, user agents that support the suggested
default rendering implement this requirement using the CSS rules described in §10 Rendering.
The tabindex
attribute must not be specified on dialog
elements.
- dialog .
show
( [ anchor ] ) -
Displays the
dialog
element.The argument, if provided, provides an anchor point to which the element will be fixed.
- dialog .
showModal
( [ anchor ] ) -
Displays the
dialog
element and makes it the top-most modal dialog.The argument, if provided, provides an anchor point to which the element will be fixed.
This method honors the
autofocus
attribute. - dialog .
close
( [ result ] ) -
Closes the
dialog
element.The argument, if provided, provides a return value.
- dialog .
returnValue
[ = result ] -
Returns the
dialog
’s return value.Can be set, to update the return value.
When the show()
method is invoked, the user
agent must run the following steps:
- If the element already has an
open
attribute, then abort these steps. - Add an
open
attribute to thedialog
element, whose value is the empty string. - If the
show()
method was invoked with an argument, set up the position of thedialog
element, using that argument as the anchor. Otherwise, set thedialog
to the normal alignment mode. - Run the dialog focusing steps for the
dialog
element.
Each Document
has a stack of dialog
elements known as the pending dialog stack. When a Document
is created, this stack must be
initialized to be empty.
When an element is added to the pending dialog stack, it must also be added to the top layer. When an element is removed from the pending dialog stack, it must be removed from the top layer. [FULLSCREEN]
When the showModal()
method is invoked,
the user agent must run the following steps:
- Let subject be the
dialog
element on which the method was invoked. - If subject already has an
open
attribute, then throw anInvalidStateError
exception and abort these steps. - If subject is not in a
Document
, then throw anInvalidStateError
exception and abort these steps. - Add an
open
attribute to subject, whose value is the empty string. - If the
showModal()
method was invoked with an argument, set up the position of subject, using that argument as the anchor. Otherwise, set thedialog
to the centered alignment mode. - Let subject’s node document be blocked by the modal dialog subject.
- Push subject onto subject’s node document’s pending dialog stack.
- Run the dialog focusing steps for subject.
The dialog focusing steps for a dialog
element subject are as follows:
- If for some reason subject is not a control group owner at this point, or if it is inert, abort these steps.
-
Let control be the first non-inert focusable area in subject’s control group whose DOM anchor has an
autofocus
attribute specified.If there isn’t one, then let control be the first non-inert focusable area in subject’s control group.
If there isn’t one of those either, then let control be subject.
- Run the focusing steps for control.
If at any time a dialog
element is removed from a Document
, then if that dialog
is in that Document
’s pending dialog stack, the following steps must be run:
- Let subject be that
dialog
element and document be theDocument
from which it is being removed. - Remove subject from document’s pending dialog stack.
- If document’s pending dialog stack is not empty, then let document be blocked by the modal dialog that is at the top of document’s pending dialog stack. Otherwise, let document be no longer blocked by a modal dialog at all.
When the close()
method is invoked, the user
agent must close the dialog that the method was invoked on. If the method was invoked
with an argument, that argument must be used as the return value; otherwise, there is no return
value.
When a dialog
element subject is to be closed, optionally with a return value result, the user agent
must run the following steps:
- If subject does not have an
open
attribute, then abort these steps. - Remove subject’s
open
attribute. - If the argument result was provided, then set the
returnValue
attribute to the value of result. -
If subject is in its
Document
’s pending dialog stack, then run these substeps:- Remove subject from that pending dialog stack.
- If that pending dialog stack is not empty, then let subject’s node document be blocked by the modal dialog that is at the top of the pending dialog stack. Otherwise, let document be no longer blocked by a modal dialog at all.
- Queue a task to fire a simple event named
close
at subject.
The returnValue
IDL attribute, on
getting, must return the last value to which it was set. On setting, it must be set to the new
value. When the element is created, it must be set to the empty string.
Canceling dialogs: When a Document
’s pending dialog
stack is not empty, user agents may provide a user interface that, upon activation, queues a task to fire a simple event named cancel
that is cancelable at the top dialog
element on
the Document
’s pending dialog stack. The default action of this event
must be to check if that element has an open
attribute, and
if it does, close the dialog with no return value.
An example of such a UI mechanism would be the user pressing the "Escape" key.
All dialog
elements are always in one of three modes: normal alignment, centered alignment, and magic alignment. When a dialog
element
is created, it must be placed in the normal alignment mode. In this mode, normal CSS
requirements apply to the element. The centered alignment mode is only used for dialog
elements that are in the top layer. [FULLSCREEN] [CSS-2015]
When an element subject is placed in centered alignment mode, and when it is in that mode and has new rendering boxes created, the user agent must set up the element such that its top static position, for the purposes of calculating the used value of the top property, is the value that would place the element’s top margin edge as far from the top of the viewport as the element’s bottom margin edge from the bottom of the viewport, if the element’s height is less than the height of the viewport, and otherwise is the value that would place the element’s top margin edge at the top of the viewport.
If there is a dialog
element with centered alignment and that is being rendered when its browsing context changes viewport width (as
measured in CSS pixels), then the user agent must recreate the element’s boxes, recalculating its
top static position as in the previous paragraph.
This top static position of a dialog
element with centered alignment must remain the element’s top static position until its boxes are recreated. (The element’s static
position is only used in calculating the used value of the top property in certain situations;
it’s not used, for instance, to position the element if its position property is set to static.)
When a user agent is to set up the position of an element subject using an anchor anchor, it must run the following steps:
-
If anchor is a
MouseEvent
object, then run these substeps:- If anchor’s target element does not have a rendered box, or is in a different document than subject, then let subject be in the centered alignment mode, and abort the set up the position steps.
- Let anchor element be an anonymous element rendered as a box with zero height and width (so its margin and border boxes both just form a point), positioned so that its top and left are at the coordinate identified by the event, and whose properties all compute to their initial values.
Otherwise, let anchor element be anchor.
- Put subject in the magic alignment mode, aligned to anchor element.
While an element A has magic alignment, aligned to an element B, the following requirements apply:
-
If at any time either A or B cease having rendered boxes, A and B cease being in the same
Document
, or B ceases being earlier than A in tree order, then, if subject is in the pending dialog stack, let subject’s mode become centered alignment, otherwise, let subject’s mode become normal alignment. -
A’s position property must compute to the keyword 'absolute-anchored' rather than whatever it would otherwise compute to (i.e., the position property’s specified value is ignored).
The 'absolute-anchored' keyword’s requirements are described below.
-
The anchor points for A and B are defined as per the appropriate entry in the following list:
- If the computed value of anchor-point is none on both A and B
- The anchor points of A and B are the center points of their respective first boxes' border boxes.
- If the computed value of anchor-point is none on A and a specific point on B
-
The anchor point of B is the point given by its anchor-point property.
If the anchor point of B is the center point of B’s first box’s border box, then A’s anchor point is the center point of its first box’s margin box.
Otherwise, A’s anchor point is on one of its margin edges. Consider four hypothetical half-infinite lines L1, L2, L3, and L4 that each start in the center of B’s first box’s border box, and that extend respectively through the top left corner, top right corner, bottom right corner, and bottom left corner of B’s first box’s border box. A’s anchor point is determined by the location of B’s anchor point relative to these four hypothetical lines, as follows:
If the anchor point of B lies on L1 or L2, or inside the area bounded by L1 and L2 that also contains the points above B’s first box’s border box, then let A’s anchor point be the horizontal center of A’s bottom margin edge.
Otherwise, if the anchor point of B lies on L3 or L4, or inside the area bounded by L3 and L4 that also contains the points below B’s first box’s border box, then let A’s anchor point be the horizontal center of A’s top margin edge.
Otherwise, if the anchor point of B lies inside the area bounded by L4 and L1 that also contains the points to the left of B’s first box’s border box, then let A’s anchor point be the vertical center of A’s right margin edge.
Otherwise, the anchor point of B lies inside the area bounded by L2 and L3 that also contains the points to the right of B’s first box’s border box; let A’s anchor point be the vertical center of A’s left margin edge.
- If the computed value of anchor-point is a specific point on A and none on B
-
The anchor point of A is the point given by its anchor-point property.
If the anchor point of A is the center point of A’s first box’s margin box, then B’s anchor point is the center point of its first box’s border box.
Otherwise, B’s anchor point is on one of its border edges. Consider four hypothetical half-infinite lines L1, L2, L3, and L4 that each start in the center of A’s first box’s margin box, and that extend respectively through the top left corner, top right corner, bottom right corner, and bottom left corner of A’s first box’s margin box. B’s anchor point is determined by the location of A’s anchor point relative to these four hypothetical lines, as follows:
If the anchor point of A lies on L1 or L2, or inside the area bounded by L1 and L2 that also contains the points above A’s first box’s margin box, then let B’s anchor point be the horizontal center of B’s bottom border edge.
Otherwise, if the anchor point of A lies on L3 or L4, or inside the area bounded by L3 and L4 that also contains the points below A’s first box’s margin box, then let B’s anchor point be the horizontal center of B’s top border edge.
Otherwise, if the anchor point of A lies inside the area bounded by L4 and L1 that also contains the points to the left of A’s first box’s margin box, then let B’s anchor point be the vertical center of B’s right border edge.
Otherwise, the anchor point of A lies inside the area bounded by L2 and L3 that also contains the points to the right of A’s first box’s margin box; let B’s anchor point be the vertical center of B’s left border edge.
- If the computed value of anchor-point is a specific point on both A and B
- The anchor points of A and B are the points given by their respective anchor-point properties.
The rules above generally use A’s margin box, but B’s border box. This is because while A always has a margin box, and using the margin box allows for the dialog to be positioned offset from the box it is annotating, B sometimes does not have a margin box (e.g., if it is a table-cell), or has a margin box whose position may be not entirely clear (e.g., in the face of margin collapsing and clear handling of in-flow blocks).
In cases where B does not have a border box but its border box is used by the algorithm above, user agents must use its first box’s content area instead. (This is in particular an issue with boxes in tables that have border-collapse set to collapse.)
-
When an element’s position property computes to 'absolute-anchored', the float property does not apply and must compute to none, the display property must compute to a value as described by the table in the section of CSS 2.1 describing the relationships between display, position, and float, and the element’s box must be positioned using the rules for absolute positioning but with its static position set such that if the box is positioned in its static position, its anchor point is exactly aligned over the anchor point of the element to which it is magically aligned. Elements aligned in this way are absolutely positioned. For the purposes of determining the containing block of other elements, the 'absolute-anchored' keyword must be treated like the absolute keyword.
The trivial example of an element that does not have a rendered box is one whose display property computes to none. However, there are many other cases; e.g., table columns do not have boxes (their properties merely affect other boxes).
If an element to which another element is anchored changes rendering, the anchored element will be repositioned accordingly. (In other words, the requirements above are live, they are not just calculated once per anchored element.)
The 'absolute-anchored'
keyword is not a keyword that can be specified in CSS; the position property can only compute to
this value if the dialog
element is positioned via the APIs described above.
User agents in visual interactive media should allow the user to pan the viewport to access all
parts of a dialog
element’s border box, even if the element is larger than the viewport and the viewport would otherwise not have a scroll mechanism (e.g., because the viewport’s overflow property is set to hidden).
The open
IDL attribute must reflect the open
content attribute.
4.11.7.1. Anchor points
This section will eventually be moved to a CSS specification; it is specified here only on an interim basis until an editor can be found to own this.
Name: | anchor-point |
---|---|
Value: | [ none | <position> ] |
Initial: | none |
Applies to: | all elements |
Inherited: | no |
Percentages: | refer to width or height of box; see prose |
Media: | visual |
Computed value: | The specified value, but with any lengths replaced by their corresponding absolute length |
Canonical order: | per grammar |
Animatable: | no |
The anchor-point property specifies a point to which dialog boxes are to be aligned.
If the value is a <position>, the anchor point is the point given by the value, which must be interpreted relative to the element’s first rendered box’s margin box. Percentages must be calculated relative to the element’s first rendered box’s margin box (specifically, its width for the horizontal position and its height for the vertical position). [CSS-VALUES] [CSS-2015]
If the value is the keyword none, then no explicit anchor point is defined. The user agent
will pick an anchor point automatically if necessary (as described in the definition of the open()
method above).