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:
These facets are exposed on elements using the command API:
commandTypeExposes the Type facet of the command.
idExposes the ID facet of the command.
commandLabelExposes the Label facet of the command.
titleExposes the Hint facet of the command.
commandIconExposes the Icon facet of the command.
accessKeyLabelExposes the Access Key facet of the command.
commandHiddenExposes the Hidden State facet of the command.
commandDisabledExposes the Disabled State facet of the command.
commandCheckedExposes the Checked State facet of the command.
click()Triggers the Action of the command.
The commandType
attribute must return a string whose value is either "command", "radio", or "checkbox", depending on whether the Type of the command defined by the
element is "command", "radio", or "checkbox" respectively. If the
element does not define a command, it must return null.
The commandLabel
attribute must return the command's Label, or null if the element
does not define a command or does not specify a Label.
The commandIcon
attribute must return the absolute URL of the command's
Icon. If the element does
not specify an icon, or if the element does not define a command,
then the attribute must return null.
The commandHidden
attribute must return true if the command's Hidden State is that the
command is hidden, and false if the command is not hidden. If the
element does not define a command, the attribute must return
null.
The commandDisabled
attribute must return true if the command's Disabled State is that
the command is disabled, and false if the command is not disabled.
This attribute is not affected by the command's Hidden State. If the
element does not define a command, the attribute must return
null.
The commandChecked
attribute must return true if the command's Checked State is that the
command is checked, and false if it is that the command is not
checked. If the element does not define a command, the attribute
must return null.
The ID facet
is exposed by the id IDL attribute, the
Hint facet is exposed by the
title IDL attribute, and the AccessKey facet is exposed by
the accessKeyLabel IDL
attribute.
commandsReturns an HTMLCollection of the elements in the
Document that define commands and have IDs.
The commands attribute
of the document's Document interface must return an
HTMLCollection rooted at the Document
node, whose filter matches only elements that define commands and have IDs.
User agents may expose the commands whose Hidden State facet is false
(visible) and whose elements are in a
Document. For example, such commands could be
listed in the user agent's menu bar. User agents are encouraged to
do this especially for commands that have Access Keys, as a way to
advertise those keys to the user.
a element to define a commandAn a element with an href attribute defines a command.
The Type of the command is "command".
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
The Label of the command
is the string given by the element's textContent IDL
attribute.
The Hint of the command
is the value of the title attribute
of the element. If the attribute is not present, the Hint is the empty string.
The Icon of the command
is the absolute URL obtained from resolving the value of the src attribute of the first
img element descendant of the element in tree
order, relative to that element, if there is such an element
and resolving its attribute is successful. Otherwise, there is no
Icon for the command.
The AccessKey of the command is the element's assigned access key, if any.
The Hidden State
of the command is true (hidden) if the element has a hidden 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 Checked State of the command is always false. (The command is never checked.)
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.
button element to define a commandA button element always defines a command.
The Type, ID, Label, Hint, Icon, Access Key, Hidden State, Checked State, 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.
input element to define a commandAn 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 Type of the command
is "radio" if the type
attribute is in the Radio
Button state, "checkbox" if the type attribute is in the Checkbox state, and
"command" otherwise.
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
The Label of the command depends on the Type of the command:
If the Type is "command",
then it is the string given by the value attribute, if any, and a
UA-dependent, locale-dependent value that the UA uses to label the
button itself if the attribute is absent.
Otherwise, the Type is
"radio" or "checkbox". 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 value of the value
attribute, if present, is the Label. Otherwise, the Label is the empty string.
The Hint of the command
is the value of the title attribute
of the input element. If the attribute is not present, the
Hint is the empty
string.
If the element's type
attribute is in the Image
Button state, and the element has a src attribute, and that attribute's
value can be successfully resolved relative to the element, then the Icon of the command is the
absolute URL obtained from resolving that attribute
that way. Otherwise, there is no Icon for the command.
The AccessKey of the command is the element's assigned access key, if any.
The Hidden State
of the command is true (hidden) if the element has a hidden 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 Checked State of the command is true if the command is of Type "radio" or "checkbox" and the element is checked 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.
option element to define a commandAn 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 Type of the command
is "radio" if the option's nearest ancestor
select element has no multiple attribute, and
"checkbox" if it does.
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous 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 whitespace
stripped, and with any sequences of two or more space characters replaced by a single
U+0020 SPACE character.
The Hint of the command
is the string given by the element's title attribute, if any, and the empty
string if the attribute is absent.
There is no Icon for the command.
The AccessKey of the command is the element's assigned access key, if any.
The Hidden State
of the command is true (hidden) if the element has a hidden 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.
The Checked State of the command is true (checked) if the element's selectedness is true, and false otherwise.
The Action of the
command depends on its Type. If the command is of Type "radio" then it must pick the option
element. Otherwise, it must toggle the option
element.
command element to define
a commandA command element that does not have a command attribute defines a command.
The Type of the command
is "radio" if the command's type attribute is
"radio", "checkbox" if the attribute's value is
"checkbox", and "command" otherwise.
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous 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 Hint of the command
is the string given by the element's title attribute, if any, and the
empty string if the attribute is absent.
The Icon for the command
is the absolute URL obtained from resolving the value of the element's icon attribute, relative to the
element, if it has such an attribute and resolving it is
successful. Otherwise, there is no Icon for the command.
The AccessKey of the command is the element's assigned access key, if any.
The Hidden State
of the command is true (hidden) if the element has a hidden 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 Checked State
of the command is true (checked) if the element has a checked 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.
command attribute on command elements to define a command indirectlyA command element with a master command
defines a command.
The Type of the command is the Type of the master command.
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
The Label of the command is the Label of the master command.
If the element has a title
attribute, then the Hint of
the command is the value of that title attribute. Otherwise, the Hint of the command is the Hint of the master
command.
The Icon of the command is the Icon of the master command.
The AccessKey of the command is the element's assigned access key, if any.
The Hidden State of the command is the Hidden State of the master command.
The Disabled State of the command is the Disabled State of the master command.
The Checked State of the command is the Checked State of the master command.
The Action of the command is to invoke the Action of the master command.
accesskey attribute on a label element to define a commandA label element that has an assigned access
key and a labeled control and whose
labeled control defines a
command, itself defines a
command.
The Type of the command is "command".
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
The Label of the command
is the string given by the element's textContent IDL
attribute.
The Hint of the command
is the value of the title attribute
of the element.
There is no Icon for the command.
The AccessKey of the command is the element's assigned access key.
The Hidden State, Disabled State, and Action facets of the command are the same as the respective facets of the element's labeled control.
The Checked State of the command is always false. (The command is never checked.)
accesskey attribute on a legend element to define a commandA 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 Type of the command is "command".
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
The Label of the command
is the string given by the element's textContent IDL
attribute.
The Hint of the command
is the value of the title attribute
of the element.
There is no Icon for the command.
The AccessKey of the command is the element's assigned access key.
The Hidden State,
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.
The Checked State of the command is always false. (The command is never checked.)
accesskey attribute to define a command on other elementsAn 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 Type of the command is "command".
The ID of the command is
the value of the id attribute of the
element, if the attribute is present and not empty. Otherwise the
command is an anonymous command.
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 Hint of the command
is the value of the title attribute
of the element. If the attribute is not present, the Hint is the empty string.
There is no Icon for the command.
The AccessKey of the command is the element's assigned access key.
The Hidden State
of the command is true (hidden) if the element has a hidden 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 Checked State of the command is always false. (The command is never checked.)
The Action of the command is to run the following steps:
click event at the element.dialog elementdt element.th element.openinterface 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.
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 the rendering section.
show( [ anchor ] )Displays the dialog element.
The argument, if provided, provides an anchor point to which the element will be fixed.
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.
close( [ result ] )Closes the dialog element.
The argument, if provided, provides a return value.
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 the dialog element, whose value is the empty
string.
If the show() method
was invoked with an argument, set up the position of
the dialog element, using that argument as the anchor.
Otherwise, set up the default static position of 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 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 dialog be the dialog
element on which the method was invoked.
If dialog already has an open attribute, then throw an
InvalidStateError exception and abort these
steps.
If dialog is not in a
Document, then throw an
InvalidStateError exception and abort these
steps.
Add an open attribute
to dialog, whose value is the empty
string.
If the showModal()
method was invoked with an argument, set up the
position of dialog, using that argument
as the anchor. Otherwise, set up the default static
position of the dialog element.
Let dialog's Document be
blocked by the modal
dialog dialog.
Push dialog onto dialog's Document's pending
dialog stack.
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 dialog be that dialog
element and document be the
Document from which it is being removed.
Remove dialog 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 dialog is
to be closed, optionally with a
return value result, the user agent must run the
following steps:
If dialog does not have an open attribute, then throw an
InvalidStateError exception and abort these
steps.
Remove dialog's open attribute.
If the argument was passed a result,
then set the returnValue attribute to the
value of result.
If dialog is in its Document's
pending dialog stack, then run these substeps:
Remove dialog from that pending dialog stack.
If that pending dialog stack is not empty,
then let dialog's 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 dialog.
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 close the dialog with no return value.
An example of such a UI mechanism would be the user pressing the "Escape" key.
When a user agent is to set up the default static position of an element dialog without an anchor, it 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.
This top static position must remain the element's top static position until it is next changed by the above algorithm or the next one. (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 dialog 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 dialog, then 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.
Let dialog be magically aligned to anchor element.
While an element A is magically aligned to an element B, A and B both have rendered boxes, and B is not a descendant of A, the following requirements apply:
A's 'position' property must compute to the keyword 'absolute-anchored'.
Let A and B's anchor points be defined as per the appropriate entry in the following list:
The anchor points of A and B are the center points of their respective first boxes' border boxes.
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 L4 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.
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 L4 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.
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'.)
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).
When an element's 'position' property must compute 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.
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.
The open IDL
attribute must reflect the open content attribute.
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.
| 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 |
| Animatable: | no |
| Canonical order: | per grammar |
The 'anchor-point' property specifies a point to which dialog boxes are to be aligned.
If the value is a <position>, the alignment 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). [CSSVALUES] [CSS]
If the value is the keyword 'none', then no explicit alignment
point is defined. The user agent will pick an alignment point
automatically if necessary (as described in the definition of the
open() method above).