HTML5

If the attribute is removed, then the details should be hidden. If the attribute is added, the details should be shown.

The user agent should allow the user to request that the details 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 value open. To honor a request for the details to be hidden, the user agent must remove the open attribute from the element.

The open attribute must reflect the open content attribute.

The type, label, icon, disabled, checked, and radiogroup IDL attributes must reflect the respective content attributes of the same name.

The element's activation behavior depends on the value of the type attribute of the element, as follows:

If the type attribute is in the Checkbox state

If the element has a checked attribute, the UA must remove that attribute. Otherwise, the UA must add a checked attribute, with the literal value checked. The UA must then fire a click event at the element.

If the type attribute is in the Radio state

If the element has a parent, then the UA must walk the list of child nodes of that parent element, and for each node that is a command element, if that element has a radiogroup attribute whose value exactly matches the current element's (treating missing radiogroup attributes as if they were the empty string), and has a checked attribute, must remove that attribute.

Then, the element's checked attribute attribute must be set to the literal value checked and the user agent must fire a click event at the element.

Otherwise

The element has no activation behavior.

Firing a synthetic click event at the element does not cause any of the actions described above to happen.

The type and label IDL attributes must reflect the respective content attributes of the same name.

4.11.4.2 Building menus and toolbars

Status: Last call for comments

A menu (or toolbar) consists of a list of zero or more of the following components:

• Commands, which can be marked as default commands
• Separators
• Other menus (which allows the list to be nested)

The list corresponding to a particular menu element is built by iterating over its child nodes. For each child node in tree order, the required behavior depends on what the node is, as follows:

An element that defines a command

Append the command to the menu, respecting its facets.

An hr element

An option element that has a value attribute set to the empty string, and has a disabled attribute, and whose textContent consists of a string of one or more hyphens (U+002D HYPHEN-MINUS)

Append a separator to the menu.

An li element

A label element

Iterate over the children of the element.

A menu element with no label attribute

A select element

Append a separator to the menu, then iterate over the children of the menu or select element, then append another separator.

A menu element with a label attribute

An optgroup element with a label attribute

Append a submenu to the menu, using the value of the element's label attribute as the label of the menu. The submenu must be constructed by taking the element and creating a new menu for it using the complete process described in this section.

Any other node

Ignore the node.

Once all the nodes have been processed as described above, the user agent must the post-process the menu as follows:

1. Except for separators, any menu item with no label, or whose label is the empty string, must be removed.
2. Any sequence of two or more separators in a row must be collapsed to a single separator.
3. Any separator at the start or end of the menu must be removed.

When an element's context menu is requested (e.g. by the user right-clicking the element, or pressing a context menu key), the UA must fire a simple 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 UA-dependent, as it will vary based on platform conventions.

The default action of the contextmenu event depends on whether the element or one of its ancestors has a context menu assigned (using the contextmenu attribute) or not. If there is no context menu assigned, the default action must be for the user agent to show its default context menu, if it has one.

If the element or one of its ancestors does have a context menu assigned, then the user agent must fire a simple event named show at the menu element of the context menu of the nearest ancestor (including the element itself) with one assigned.

The default action of this event is that the user agent must show a context menu built from the menu element.

The user agent may also provide access to its default context menu, if any, with the context menu shown. For example, it could merge the menu items from the two menus together, or provide the page's context menu as a submenu of the default menu.

If the user dismisses the menu without making a selection, nothing in particular happens.

If the user selects a menu item that represents a command, then the UA must invoke that command's Action.

Context menus must not, while being shown, reflect changes in the DOM; they are constructed as the default action of the show event and must remain as constructed until dismissed.

User agents may provide means for bypassing the context menu processing model, ensuring that the user can always access the UA's default context menus. For example, the user agent could handle right-clicks that have the Shift key depressed in such a way that it does not fire the contextmenu event and instead always shows the default context menu.

The contextMenu attribute must reflect the contextmenu content attribute.

4.11.4.4 Toolbars

Status: Last call for comments

When a menu element has a type attribute in the toolbar state, then the user agent must build the menu for that menu element, and use the result in the rendering.

The user agent must reflect changes made to the menu's DOM, by immediately rebuilding the menu.

The commandType attribute must return a string whose value is either "command", "radio", or "checked", depending on whether the Type of the command defined by the element is "command", "radio", or "checked" respectively. If the element does not define a command, it must return null.

The label attribute must return the command's Label, or null if the element does not define a command or does not specify a Label. This attribute will be shadowed by the label IDL attribute on option and command elements.

The icon 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. This attribute will be shadowed by the icon IDL attribute on command elements.

The disabled 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 false. This attribute will be shadowed by the disabled IDL attribute on button, input, option, and command elements.

The checked 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 false. This attribute will be shadowed by the checked IDL attribute on input and command elements.

The ID facet is exposed by the id IDL attribute, the Hint facet is exposed by the title IDL attribute, the AccessKey facet is exposed by the accessKeyLabel IDL attribute, and the Hidden State facet is exposed by the hidden IDL attribute.

The commands attribute of the document's HTMLDocument interface must return an HTMLCollection rooted at the Document node, whose filter matches only elements that define commands and have IDs.

4.11.5.1 Using the a element to define a command

Status: Last call for comments

An 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, 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 always false. (The command is always enabled.)

The Checked State of the command is always false. (The command is never checked.)

The Action of the command is to fire a click event at the element.

4.11.5.2 Using the button element to define a command

Status: Last call for comments

A 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 mirrors the disabled state of the button.

4.11.5.3 Using the input element to define a command

Status: Last call for comments

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 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 mirrors the disabled state of the control.

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.

4.11.5.4 Using the option element to define a command

Status: Last call for comments

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 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 the value of the option element's textContent IDL attribute if there isn'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.

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 (disabled) if the element is disabled or if its nearest ancestor select element is disabled, 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.

4.11.5.5 Using the command element to define a command

Status: Last call for comments

A command element 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 (disabled) 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.

4.11.5.6 Using the accesskey attribute on a label element to define a command

Status: Last call for comments

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 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.)

4.11.5.7 Using the accesskey attribute on a legend element to define a command

Status: Last call for comments

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 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.)

4.11.5.8 Using the accesskey attribute to define a command on other elements

Status: Last call for comments

An element that has an assigned access key defines a command.

If one of the other 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 facet of the command is always false. (The command is always enabled.)

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:

1. If the element is focusable, run the focusing steps for the element.
2. If the element has a defined activation behavior, run synthetic click activation steps on the element.
3. Otherwise, if the element does not have a defined activation behavior, fire a click event at the element.

4.12.2 Following hyperlinks

Status: Last call for comments

When a user follows a hyperlink, the user agent must resolve the URL given by the href attribute of that hyperlink, relative to the hyperlink element, and if that is successful, must navigate a browsing context to the resulting absolute URL. In the case of server-side image maps, the URL of the hyperlink must further have its hyperlink suffix appended to it.

If resolving the URL fails, the user agent may report the error to the user in a user-agent-specific manner, may navigate to an error page to report the error, or may ignore the error and do nothing.

If the user indicated a specific browsing context when following the hyperlink, or if the user agent is configured to follow hyperlinks by navigating a particular browsing context, then that must be the browsing context that is navigated.

Otherwise, if the hyperlink element is an a or area element that has a target attribute, then the browsing context that is navigated must be chosen by applying the rules for choosing a browsing context given a browsing context name, using the value of the target attribute as the browsing context name. If these rules result in the creation of a new browsing context, it must be navigated with replacement enabled.

Otherwise, if the hyperlink element is a sidebar hyperlink and the user agent implements a feature that can be considered a secondary browsing context, such a secondary browsing context may be selected as the browsing context to be navigated.

Otherwise, if the hyperlink element is an a or area element with no target attribute, but one of the child nodes of the head element is a base element with a target attribute, then the browsing context that is navigated must be chosen by applying the rules for choosing a browsing context given a browsing context name, using the value of the target attribute of the first such base element as the browsing context name. If these rules result in the creation of a new browsing context, it must be navigated with replacement enabled.

Otherwise, the browsing context that must be navigated is the same browsing context as the one which the hyperlink element itself is in.

The navigation must be done with the browsing context that contains the Document object with which the hyperlink's element in question is associated as the source browsing context.

4.12.2.1 Hyperlink auditing

Status: Last call for comments. ISSUE-1 (PINGPOST) and ISSUE-2 (PINGUI) block progress to Last Call

If an a or area hyperlink element has a ping attribute, and the user follows the hyperlink, and the hyperlink's URL can be resolved, relative to the hyperlink element, without failure, then the user agent must take the ping attribute's value, split that string on spaces, resolve each resulting token relative to the hyperlink element, and then should send a request (as described below) to each of the resulting absolute URLs. (Tokens that fail to resolve are ignored.) This may be done in parallel with the primary request, and is independent of the result of that request.

User agents should allow the user to adjust this behavior, for example in conjunction with a setting that disables the sending of HTTP Referer (sic) headers. Based on the user's preferences, UAs may either ignore the ping attribute altogether, or selectively ignore URLs in the list (e.g. ignoring any third-party URLs).

For URLs that are HTTP URLs, the requests must be performed by fetching the specified URLs using the POST method, with an entity body with the MIME type text/ping consisting of the four-character string "PING", from the origin of the Document containing the hyperlink. All relevant cookie and HTTP authentication headers must be included in the request. Which other headers are required depends on the URLs involved.

If both the address of the Document object containing the hyperlink being audited and the ping URL have the same origin

The request must include a Ping-From HTTP header with, as its value, the address of the document containing the hyperlink, and a Ping-To HTTP header with, as its value, the address of the absolute URL of the target of the hyperlink. The request must not include a Referer (sic) HTTP header.

Otherwise, if the origins are different, but the document containing the hyperlink being audited was not retrieved over an encrypted connection

The request must include a Referer (sic) HTTP header with, as its value, the current address of the document containing the hyperlink, a Ping-From HTTP header with the same value, and a Ping-To HTTP header with, as its value, the address of the target of the hyperlink.

Otherwise, the origins are different and the document containing the hyperlink being audited was retrieved over an encrypted connection

The request must include a Ping-To HTTP header with, as its value, the address of the target of the hyperlink. The request must neither include a Referer (sic) HTTP header nor include a Ping-From HTTP header.

To save bandwidth, implementors might also wish to consider omitting optional headers such as Accept from these requests.

User agents must, unless otherwise specified by the user, honor the HTTP headers (including, in particular, redirects and HTTP cookie headers), but must ignore any entity bodies returned in the responses. User agents may close the connection prematurely once they start receiving an entity body. [COOKIES]

For URLs that are not HTTP URLs, the requests must be performed by fetching the specified URL normally, and discarding the results.

When the ping attribute is present, user agents should clearly indicate to the user that following the hyperlink will also cause secondary requests to be sent in the background, possibly including listing the actual target URLs.

For example, a visual user agent could include the hostnames of the target ping URLs along with the hyperlink's actual URL in a status bar or tooltip.

To determine which link types apply to a link, a, or area element, the element's rel attribute must be split on spaces. The resulting tokens are the link types that apply to that element.

Some of the types described below list synonyms for these values. These are to be handled as specified by user agents, but must not be used in documents.

If the alternate keyword is used with the type attribute set to the value application/rss+xml or the value application/atom+xml, then it indicates that the referenced document is a syndication feed (though not necessarily syndicating exactly the same content as the current page).

<link rel="alternate" type="application/atom+xml" href="data.xml">

<p>You can access the planets database using Atom feeds:</p>
<ul>
 <li><a href="recently-visited-planets.xml" rel="alternate" type="application/atom+xml">Recently Visited Planets</a></li>
 <li><a href="known-bad-planets.xml" rel="alternate" type="application/atom+xml">Known Bad Planets</a></li>
 <li><a href="unexplored-planets.xml" rel="alternate" type="application/atom+xml">Unexplored Planets</a></li>
</ul>

Synonyms: For historical reasons, user agents must also treat the keyword "archive" like the archives keyword.

Synonyms: For historical reasons, user agents must also treat link, a, and area elements that have a rev attribute with the value "made" as having the author keyword specified as a link relationship.

The specified resource is an icon representing the page or site, and should be used by the user agent when representing the page in the user interface.

There is no default type for resources given by the icon keyword. However, for the purposes of determining the type of the resource, user agents must expect the resource to be an image.

To parse and process the attribute's value, the user agent must first split the attribute's value on spaces, and must then parse each resulting keyword to determine what it represents.

Other keywords must be further parsed as follows to determine what they represent:

• If the keyword doesn't contain exactly one U+0078 LATIN SMALL LETTER X character (x), then this keyword doesn't represent anything. Abort these steps for that keyword.

• Let width string be the string before the "x".

• Let height string be the string after the "x".

• If either width string or height string start with a U+0030 DIGIT ZERO (0) character or contain any characters other than characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then this keyword doesn't represent anything. Abort these steps for that keyword.

• Apply the rules for parsing non-negative integers to width string to obtain width.

• Apply the rules for parsing non-negative integers to height string to obtain height.

• The keyword represents that the resource contains a bitmap icon with a width of width device pixels and a height of height device pixels.

If the attribute is not specified, then the user agent must assume that the given icon is appropriate, but less appropriate than an icon of a known and appropriate size.

Synonyms: For historical reasons, user agents must also treat the keyword "copyright" like the license keyword.

If a user agent follows a link defined by an a or area element that has the noreferrer keyword, the user agent must not include a Referer (sic) HTTP header (or equivalent for other protocols) in the request.

This keyword also causes the opener attribute to remain null if the hyperlink creates a new browsing context.

Quirk: If the document has been set to quirks mode and the Content-Type metadata of the external resource is not a supported style sheet type, the user agent must instead assume it to be text/css.

Synonyms: For historical reasons, user agents must also treat the keywords "top", "contents", and "toc" like the index keyword.

When two links have both the up and index keywords specified together in the same scope and contradict each other by having a different number of up keywords, the link with the greater number of up keywords must be taken as giving the depth of the document.

Synonyms: For historical reasons, user agents must also treat the keywords "begin" and "start" like the first keyword.

Synonyms: For historical reasons, user agents must also treat the keyword "end" like the last keyword.

Synonyms: For historical reasons, user agents must also treat the keyword "previous" like the prev keyword.

Conformance checkers must use the information given on the WHATWG Wiki RelExtensions page to establish if a value is allowed or not: values defined in this specification or marked as "proposed" or "ratified" must be accepted when used on the elements for which they apply as described in the "Effect on..." field, whereas values marked as "discontinued" or not listed in either this specification or on the aforementioned page must be rejected as invalid. Conformance checkers may cache this information (e.g. for performance reasons or to avoid the use of unreliable network connectivity).

When an author uses a new type not defined by either this specification or the Wiki page, conformance checkers should offer to add the value to the Wiki, with the details described above, with the "proposed" status.

4.14 Matching HTML elements using selectors

Status: Last call for comments

4.14.1 Case-sensitivity

Status: Last call for comments

Attribute and element names of HTML elements in HTML documents must be treated as ASCII case-insensitive.

Classes from the class attribute of HTML elements in documents that are in quirks mode must be treated as ASCII case-insensitive.

Attribute selectors on an HTML element in an HTML document must treat the values of attributes with the following names as ASCII case-insensitive:

• accept
• accept-charset
• align
• alink
• axis
• bgcolor
• charset
• checked
• clear
• codetype
• color
• compact
• declare
• defer
• dir
• direction
• disabled
• enctype
• face
• frame
• hreflang
• http-equiv
• lang
• language
• link
• media
• method
• multiple
• nohref
• noresize
• noshade
• nowrap
• readonly
• rel
• rev
• rules
• scope
• scrolling
• selected
• shape
• target
• text
• type
• valign
• valuetype
• vlink

All other attribute values on HTML elements must be treated as case-sensitive.

4.14.2 Pseudo-classes

There are a number of dynamic selectors that can be used with HTML. This section defines when these selectors match HTML elements.

:link

:visited

All a elements that have an href attribute, all area elements that have an href attribute, and all link elements that have an href attribute, must match one of :link and :visited.

:active

The :active pseudo-class must match the following elements between the time the user begins to activate the element and the time the user stops activating the element:

• a elements that have an href attribute
• area elements that have an href attribute
• link elements that have an href attribute
• button elements that are not disabled
• input elements whose type attribute is in the Submit Button, Image Button, Reset Button, or Button state
• command elements that do not have a disabled attribute
• any other element, if it is specially focusable

For example, if the user is using a keyboard to push a button element by pressing the space bar, the element would match this pseudo-class in between the time that the element received the keydown event and the time the element received the keyup event.

:enabled

The :enabled pseudo-class must match the following elements:

• a elements that have an href attribute
• area elements that have an href attribute
• link elements that have an href attribute
• button elements that are not disabled
• input elements whose type attribute are not in the Hidden state and that are not disabled
• select elements that are not disabled
• textarea elements that are not disabled
• option elements that do not have a disabled attribute
• command elements that do not have a disabled attribute
• li elements that are children of menu elements, and that have a child element that defines a command, if the first such element's Disabled State facet is false (not disabled)

:disabled

The :disabled pseudo-class must match the following elements:

• button elements that are disabled
• input elements whose type attribute are not in the Hidden state and that are disabled
• select elements that are disabled
• textarea elements that are disabled
• option elements that have a disabled attribute
• command elements that have a disabled attribute
• li elements that are children of menu elements, and that have a child element that defines a command, if the first such element's Disabled State facet is true (disabled)

:checked

The :checked pseudo-class must match the following elements:

• input elements whose type attribute is in the Checkbox state and whose checkedness state is true
• input elements whose type attribute is in the Radio Button state and whose checkedness state is true
• command elements whose type attribute is in the Checkbox state and that have a checked attribute
• command elements whose type attribute is in the Radio state and that have a checked attribute

:indeterminate

The :indeterminate pseudo-class must match input elements whose type attribute is in the Checkbox state and whose indeterminate IDL attribute is set to true.

:default

The :default pseudo-class must match the following elements:

• button elements that are their form's default button
• input elements whose type attribute is in the Submit Button or Image Button state, and that are their form's default button

:valid

The :valid pseudo-class must match all elements that are candidates for constraint validation and that satisfy their constraints.

:invalid

The :invalid pseudo-class must match all elements that are candidates for constraint validation but that do not satisfy their constraints.

:in-range

The :in-range pseudo-class must match all elements that are candidates for constraint validation and that are neither suffering from an underflow nor suffering from an overflow.

:out-of-range

The :out-of-range pseudo-class must match all elements that are candidates for constraint validation and that are suffering from an underflow or suffering from an overflow.

:required

The :required pseudo-class must match the following elements:

• input elements that are required
• textarea elements that have a required attribute

:optional

The :optional pseudo-class must match the following elements:

• button elements
• input elements that are not required
• select elements
• textarea elements that do not have a required attribute

:read-only

:read-write

The :read-write pseudo-class must match the following elements:

• input elements to which the readonly attribute applies, but that are not immutable (i.e. that do not have the readonly attribute specified and that are not disabled)
• textarea elements that do not have a readonly attribute, and that are not disabled
• any element that is editable

The :read-only pseudo-class must match all other HTML elements.

Another section of this specification defines the target element used with the :target pseudo-class.

This specification does not define when an element matches the :hover, :focus, or :lang() dynamic pseudo-classes, as those are all defined in sufficient detail in a language-agnostic fashion in the Selectors specification. [SELECTORS]

4.15 Converting HTML to other formats

Status: Last call for comments

4.15.1 Atom

Status: Last call for comments. ISSUE-86 (atom-id-stability) blocks progress to Last Call

Given a Document source, a user agent may run the following algorithm to extract an Atom feed. This is not the only algorithm that can be used for this purpose; for instance, a user agent might instead use the hAtom algorithm. [HATOM]

1. If the Document source does not contain any article elements, then return nothing and abort these steps. This algorithm can only be used with documents that contain distinct articles.

2. Let R be an empty XML Document object whose address is user-agent defined.

3. Append a feed element in the Atom namespace to R.

4. For each meta element with a name attribute and a content attribute and whose name attribute's value is author, run the following substeps:

   1. Append an author element in the Atom namespace to the root element of R.

   2. Append a name element in the Atom namespace to the element created in the previous step.

   3. Append a text node whose data is the value of the meta element's content attribute to the element created in the previous step.

5. If there is a link element whose rel attribute's value includes the keyword icon, and that element also has an href attribute whose value successfully resolves relative to the link element, then append an icon element in the Atom namespace to the root element of R whose contents is a text node with its data set to the absolute URL resulting from resolving the value of the href attribute.

6. Append an id element in the Atom namespace to the root element of R whose contents is a text node with its data set to the document's current address.

7. Optionally: Let x be a link element in the Atom namespace. Add a rel attribute whose value is the string "self" to x. Append a text node with its data set to the (user-agent-defined) address of R to x. Append x to the root element of R.

   This step would be skipped when the document R has no convenient address. The presence of the rel="self" link is a "should"-level requirement in the Atom specification.

8. Let x be a link element in the Atom namespace. Add a rel attribute whose value is the string "alternate" to x. If the document being converted is an HTML document, add a type attribute whose value is the string "text/html" to x. Otherwise, the document being converted is an XML document; add a type attribute whose value is the string "application/xhtml+xml" to x. Append a text node with its data set to the document's current address to x. Append x to the root element of R.

9. Let subheading text be the empty string.

10. Let heading be the first element of heading content whose nearest ancestor of sectioning content is the body element, if any, or null if there is none.

11. Take the appropriate action from the following list, as determined by the type of the heading element:

    If heading is null

    Let heading text be the textContent of the title element, if there is one, or the empty string otherwise.

    If heading is a hgroup element

    If heading contains no child h1–h6 elements, let heading text be the empty string.

    Otherwise, let headings list be a list of all the h1–h6 element children of heading, sorted first by descending rank and then in tree order (so h1s first, then h2s, etc, with each group in the order they appear in the document). Then, let heading text be the textContent of the first entry in headings list, and if there are multiple entries, let subheading text be the textContent of the second entry in headings list.

    If heading is an h1–h6 element

    Let heading text be the textContent of heading.

12. Append a title element in the Atom namespace to the root element of R whose contents is a text node with its data set to heading text.

13. If subheading text is not the empty string, append a subtitle element in the Atom namespace to the root element of R whose contents is a text node with its data set to subheading text.

14. Let global update date have no value.

15. For each article element article that does not have an ancestor article element, run the following steps:

    1. Let E be an entry element in the Atom namespace, and append E to the root element of R.

    2. Let heading be the first element of heading content whose nearest ancestor of sectioning content is article, if any, or null if there is none.

    3. Take the appropriate action from the following list, as determined by the type of the heading element:

       If heading is null

       Let heading text be the empty string.

       If heading is a hgroup element

       If heading contains no child h1–h6 elements, let heading text be the empty string.

       Otherwise, let headings list be a list of all the h1–h6 element children of heading, sorted first by descending rank and then in tree order (so h1s first, then h2s, etc, with each group in the order they appear in the document). Then, let heading text be the textContent of the first entry in headings list.

       If heading is an h1–h6 element

       Let heading text be the textContent of heading.

    4. Append a title element in the Atom namespace to E whose contents is a text node with its data set to heading text.

    5. Clone article and its descendants into an environment that has scripting disabled, has no plugins, and fails any attempt to fetch any resources. Let cloned article be the resulting clone article element.

    6. Remove from the subtree rooted at cloned article any article elements other than the cloned article itself, any header, footer, or nav elements whose nearest ancestor of sectioning content is the cloned article, and the first element of heading content whose nearest ancestor of sectioning content is the cloned article, if any.

    7. If cloned article contains any ins or del elements with datetime attributes whose values parse as global date and time strings without errors, then let update date be the value of the datetime attribute that parses to the newest global date and time.

       Otherwise, let update date have no value.

       This value is used below; it is calculated here because in certain cases the next step mutates the cloned article.

    8. If the document being converted is an HTML document, then: Let x be a content element in the Atom namespace. Add a type attribute whose value is the string "html" to x. Append a text node with its data set to the result of running the HTML fragment serialization algorithm on cloned article to x. Append x to E.

       Otherwise, the document being converted is an XML document: Let x be a content element in the Atom namespace. Add a type attribute whose value is the string "xml" to x. Append a div element to x. Move all the child nodes of the cloned article node to that div element, preserving their relative order. Append x to E.

    9. Establish the value of id and has-alternate from the first of the following to apply:

       If the article node has a descendant a or area element with an href attribute that successfully resolves relative to that descendant and a rel attribute whose value includes the bookmark keyword

       Let id be the absolute URL resulting from resolving the value of the href attribute of the first such a or area element, relative to the element. Let has-alternate be true.

       If the article node has an id attribute

       Let id be the document's current address, with the fragment identifier (if any) removed, and with a new fragment identifier specified, consisting of the value of the article element's id attribute. Let has-alternate be false.

       Otherwise

       Let id be a user-agent-defined undereferenceable yet globally unique valid absolute URL. The same absolute URL should be generated for each run of this algorithm when given the same input. Let has-alternate be false.

    10. Append an id element in the Atom namespace to E whose contents is a text node with its data set to id.

    11. If has-alternate is true: Let x be a link element in the Atom namespace. Add a rel attribute whose value is the string "alternate" to x. Append a text node with its data set to id to x. Append x to E.

    12. If article has a time element descendant that has a pubdate attribute and whose nearest ancestor article element is article, and the first such element's date is not unknown, then run the following substeps, with e being the first such element:

        1. Let datetime be a global date and time whose date component is the date of e.

        2. If e's time and time-zone offset are not unknown, then let datetime's time and time-zone offset components be the time and time-zone offset of e. Otherwise, let them be midnight and no offset respectively ("00:00Z").

        3. Let publication date be the best representation of the global date and time string datetime.

        Otherwise, let publication date have no value.

    13. If update date has no value but publication date does, then let update date have the value of publication date.

        Otherwise, if publication date has no value but update date does, then let publication date have the value of update date.

    14. If update date has a value, and global update date has no value or is less recent than update date, then let global update date have the value of update date.

    15. If publication date and update date both still have no value, then let them both value a value that is a valid global date and time string representing the global date and time of the moment that this algorithm was invoked.

    16. Append an published element in the Atom namespace to E whose contents is a text node with its data set to publication date.

    17. Append an updated element in the Atom namespace to E whose contents is a text node with its data set to update date.

16. If global update date has no value, then let it have a value that is a valid global date and time string representing the global date and time of the date and time of the Document's source file's last modification, if it is known, or else of the moment that this algorithm was invoked.

17. Insert an updated element in the Atom namespace into the root element of R before the first entry in the Atom namespace whose contents is a text node with its data set to global update date.

18. Return the Atom document R.

The above algorithm does not guarantee that the output will be a conforming Atom feed. In particular, if insufficient information is provided in the document (e.g. if the document does not have any <meta name="author" content="..."> elements), then the output will not be conforming.

The Atom namespace is: http://www.w3.org/2005/Atom