Attributes

This section is non-normative.

Legend:

Attribute: abc – specs HTML4.01 and HTML5 • abc – spec HTML4.01 and HTML5 for new HTML5 elements • abc – spec HTML5
Element(s): abc – attribute suport only in HTML5

List of attributes
Attribute	Element(s)	Description	Value
`accept`	`input; form`	Hint for expected file type in file upload controls	Set of comma-separated tokens* consisting of valid MIME types or `audio/`, `video/`, or `image/*`
`accept-charset`	`form`	Character encodings to use for form submission	Ordered set of unique space-separated tokens consisting of preferred MIME names of ASCII-compatible character encodings
`action`	`form`	URL to use for form submission	Valid URL
`alt`	`area`; `img`; `input`	Replacement text for use when images are not available	Text*
`async`	`script`	Execute script asynchronously	Boolean attribute
`autobuffer`	`audio`; `video`	Hint that buffering the media resource will likely be needed	Boolean attribute
`autocomplete`	`form`; `input`	Prevent the user agent from providing autocompletions for the form control(s)	"`on`"; "`off`"
`autofocus`	`button`; `input`; `keygen`; `select`; `textarea`	Automatically focus the form control when the page is loaded	Boolean attribute
`autoplay`	`audio`; `video`	Hint that the media resource can be started automatically when the page is loaded	Boolean attribute
`challenge`	`keygen`	String to package with the generated and signed public key	Text
`charset`	`meta`	Character encoding declaration	Preferred MIME name of an encoding*
`charset`	`script`	Character encoding of the external script resource	Preferred MIME name of an encoding*
`checked`	`command`; `input`	Whether the command or control is checked	Boolean attribute
`cite`	`blockquote`; `del`; `ins`; `q`	Link to the source of the quotation or more information about the edit	Valid URL
`cols`	`textarea`	Maximum number of characters per line	Valid non-negative integer greater than zero
`colspan`	`td`; `th`	Number of columns that the cell is to span	Valid non-negative integer greater than zero
`content`	`meta`	Value of the element	Text*
`controls`	`audio`; `video`	Show user agent controls	Boolean attribute
`coords`	`area`	Coordinates for the shape to be created in an image map	Valid list of integers*
`data`	`object`	Address of the resource	Valid URL
`datetime`	`del`; `ins`	Time and date of the change	Valid global date and time string
`datetime`	`time`	Value of the element	Valid date or time string*
`defer`	`script`	Defer script execution	Boolean attribute
`disabled`	`button`; `command`; `fieldset`; `input`; `keygen`; `optgroup`; `option`; `select`; `textarea`	Whether the form control is disabled	Boolean attribute
`enctype`	`form`	Form data set encoding type to use for form submission	"`application/x-www-form-urlencoded`"; "`multipart/form-data`"; "`text/plain`"
`for`	`label`	Associatd the label with form control	ID*
`for`	`output`	Specifies controls from which the output was calculated	Unordered set of unique space-separated tokens consisting of IDs*
`form`	`button`; `fieldset`; `input`; `keygen`; `label`; `object`; `output`; `select`; `textarea`	Associates the control with a `form` element	ID*
`formaction`	`button`; `input`	URL to use for form submission	Valid URL
`formenctype`	`button`; `input`	Form data set encoding type to use for form submission	"`application/x-www-form-urlencoded`"; "`multipart/form-data`"; "`text/plain`"
`formmethod`	`button`; `input`	HTTP method to use for form submission	"`GET`"; "`POST`"; "`PUT`"; "`DELETE`"
`formnovalidate`	`button`; `input`	Bypass form control validation for form submission	Boolean attribute
`formtarget`	`button`; `input`	Browsing context for form submission	Valid browsing context name or keyword
`headers`	`td`; `th`	The header cells for this cell	Unordered set of unique space-separated tokens consisting of IDs*
`height`	`canvas`; `embed`; `iframe`; `img`; `input`; `object`; `video`	Vertical dimension	Valid non-negative integer
`high`	`meter`	Low limit of high range	Valid floating point number*
`href`	`a`; `area`; `link`	Address of the hyperlink	Valid URL
`href`	`base`	Document base URL	Valid URL
`hreflang`	`a`; `area`; `link`	Language of the linked resource	Valid BCP 47 language code
`http-equiv`	`meta`	Pragma directive	Text*
`icon`	`command`	Icon for the command	Valid URL
`ismap`	`img`	Whether the image is a server-side image map	Boolean attribute
`keytype`	`keygen`	The type of cryptographic key to generate	Text*
`label`	`command`; `menu`; `optgroup`; `option`	User-visible label	Text
`list`	`input`	List of autocomplete options	ID*
`loop`	`audio`; `video`	Whether to loop the media resource	Boolean attribute
`low`	`meter`	High limit of low range	Valid floating point number*
`manifest`	`html`	Application cache manifest	Valid URL
`max`	`input`	Maximum value	varies*
`max`	`meter`; `progress`	Upper bound of range	Valid floating point number*
`maxlength`	`input`; `textarea`	Maximum length of value	Valid non-negative integer
`media`	`a`; `area`; `link`; `source`; `style`	Applicable media	Valid media query
`method`	`form`	HTTP method to use for form submission	"`GET`"; "`POST`"; "`PUT`"; "`DELETE`"
`min`	`input`	Minimum value	varies*
`min`	`meter`	Lower bound of range	Valid floating point number*
`multiple`	`input`; `select`	Whether to allow multiple values	Boolean attribute
`name`	`button`; `fieldset`; `input`; `keygen`; `output`; `select`; `textarea`	Name of form control to use for form submission and in the `form.elements` API	Text*
`name`	`form`	Name of form to use in the `document.forms` API	Text*
`name`	`iframe`; `object`	Name of nested browsing context	Valid browsing context name or keyword
`name`	`map`	Name of image map to reference from the `usemap` attribute	Text*
`name`	`meta`	Metadata name	Text*
`name`	`param`	Name of parameter	Text
`novalidate`	`form`	Bypass form control validation for form submission	Boolean attribute
`onafterprint`	`body`	`afterprint` event handler for `Window` object	Event handler content attribute
`onbeforeprint`	`body`	`beforeprint` event handler for `Window` object	Event handler content attribute
`onbeforeunload`	`body`	`beforeunload` event handler for `Window` object	Event handler content attribute
`onblur`	`body`	`blur` event handler for `Window` object	Event handler content attribute
`onerror`	`body`	`error` event handler for `Window` object	Event handler content attribute
`onfocus`	`body`	`focus` event handler for `Window` object	Event handler content attribute
`onhashchange`	`body`	`hashchange` event handler for `Window` object	Event handler content attribute
`onload`	`body`	`load` event handler for `Window` object	Event handler content attribute
`onmessage`	`body`	`message` event handler for `Window` object	Event handler content attribute
`onoffline`	`body`	`offline` event handler for `Window` object	Event handler content attribute
`ononline`	`body`	`online` event handler for `Window` object	Event handler content attribute
`onpopstate`	`body`	`popstate` event handler for `Window` object	Event handler content attribute
`onredo`	`body`	`redo` event handler for `Window` object	Event handler content attribute
`onresize`	`body`	`resize` event handler for `Window` object	Event handler content attribute
`onstorage`	`body`	`storage` event handler for `Window` object	Event handler content attribute
`onundo`	`body`	`undo` event handler for `Window` object	Event handler content attribute
`onunload`	`body`	`unload` event handler for `Window` object	Event handler content attribute
`open`	`details`	Whether the details are visible	Boolean attribute
`optimum`	`meter`	Optimum value in gauge	Valid floating point number*
`pattern`	`input`	Pattern to be matched by the form control's value	Regular expression matching the JavaScript Pattern production
`ping`	`a`; `area`	URLs to ping	Set of space-separated tokens consisting of valid URLs
`placeholder`	`input`; `textarea`	User-visible label to be placed within the form control	Text*
`poster`	`video`	Poster frame to show prior to video playback	Valid URL
`pubdate`	`time`	Whether the element's value represents a publication time for the nearest `article` or `body`	Boolean attribute
`radiogroup`	`command`	Name of group of commands to treat as a radio button group	Text
`readonly`	`input`; `textarea`	Whether to allow the value to be edited by the user	Boolean attribute
`rel`	`a`; `area`; `link`	Relationship between the document containing the hyperlink and the destination resource	Set of space-separated tokens*
`required`	`input`; `textarea`	Whether the control is required for form submission	Boolean attribute
`reversed`	`ol`	Number the list backwards	Boolean attribute
`rows`	`textarea`	Number of lines to show	Valid non-negative integer greater than zero
`rowspan`	`td`; `th`	Number of rows that the cell is to span	Valid non-negative integer
`sandbox`	`iframe`	Security rules for nested content	Unordered set of unique space-separated tokens consisting of "`allow-same-origin`", "`allow-forms`", and "`allow-scripts`"
`scope`	`th`	Specifies which cells the header cell applies to	"`row`"; "`col`"; "`rowgroup`"; "`colgroup`"
`scoped`	`style`	Whether the styles apply to the entire document or just the parent subtree	Boolean attribute
`seamless`	`iframe`	Whether to apply the document's styles to the nested content	Boolean attribute
`selected`	`option`	Whether the option is selected by default	Boolean attribute
`shape`	`area`	The kind of shape to be created in an image map	"`circle`"; "`default`"; "`poly`"; "`rect`"
`size`	`input`; `select`	Size of the control	Valid non-negative integer greater than zero
`sizes`	`link`	Sizes of the icons (for `rel`="`icon`")	List of sizes*
`span`	`col`; `colgroup`	Number of columns spanned by the element	Valid non-negative integer greater than zero
`src`	`audio`; `embed`; `iframe`; `img`; `input`; `script`; `source`; `video`	Address of the resource	Valid URL
`start`	`ol`	Ordinal value of the first item	Valid integer
`step`	`input`	Granularity to be matched by the form control's value	Valid floating point number greater than zero, or "`any`"
`summary`	`table`	Explanatory text for complex tables for users of screen readers	Text*
`target`	`a`; `area`	Browsing context for hyperlink navigation	Valid browsing context name or keyword
`target`	`base`	Default browsing context for hyperlink navigation and form submission	Valid browsing context name or keyword
`target`	`form`	Browsing context for form submission	Valid browsing context name or keyword
`type`	`a`; `area`; `link`	Hint for the type of the referenced resource	Valid MIME type
`type`	`button`	Type of button	"`submit`"; "`reset`"; "`button`"
`type`	`button`; `input`	Type of form control	`input` type keyword
`type`	`command`	Type of command	"`command`"; "`checkbox`"; "`radio`"
`type`	`embed`; `object`; `script`; `source`; `style`	Type of embedded resource	Valid MIME type
`type`	`menu`	Type of menu	"`context`"; "`toolbar`"
`usemap`	`img`; `object`	Name of image map to use	Valid hash-name reference*
`value`	`button`; `option`	Value to be used for form submission	Text
`value`	`input`	Value of the form control	varies*
`value`	`li`	Ordinal value of the list item	Valid integer
`value`	`meter`; `progress`	Current value of the element	Valid floating point number
`value`	`param`	Value of parameter	Text
`width`	`canvas`; `embed`; `iframe`; `img`; `input`; `object`; `video`	Horizontal dimension	Valid non-negative integer
`wrap`	`textarea`	How the value of the form control is to be wrapped for form submission	"`soft`"; "`hard`"

An asterisk (*) in a cell indicates that the actual rules are more complicated than indicated in the table above.