abbr | th | Alternative label to use for the header cell when referencing the cell in other contexts | Text* |
accept | input | Hint for expected file type in file upload controls | Set of comma-separated tokens* consisting of valid MIME types with no parameters or audio/* , video/* , or image/* |
accept-charset | form | Character encodings to use for form submission | Ordered set of unique space-separated tokens, ASCII case-insensitive, consisting of preferred MIME names of ASCII-compatible character encodings* |
accesskey | HTML elements | Keyboard shortcut to activate or focus element | Ordered set of unique space-separated tokens, case-sensitive, consisting of one Unicode code point in length |
action | form | URL to use for form submission | Valid non-empty URL potentially surrounded by spaces |
alt | area ; img ; input | Replacement text for use when images are not available | Text* |
async | script | Execute script asynchronously | Boolean attribute |
autocomplete | form | Default setting for autofill feature for controls in the form | "on "; "off " |
autocomplete | input ; select ; textarea | Hint for form autofill feature | Autofill field name and related tokens* |
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 |
border | table | Explicit indication that the table element is not being used for layout purposes | The empty string, or "1 " |
challenge | keygen | String to package with the generated and signed public key | Text |
charset | meta | Character encoding declaration | Preferred MIME name of a character encoding* |
charset | script | Character encoding of the external script resource | Preferred MIME name of a character 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 potentially surrounded by spaces |
class | HTML elements | Classes to which the element belongs | Set of space-separated tokens |
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 |
command | command | Command definition | ID* |
content | meta | Value of the element | Text* |
contenteditable | HTML elements | Whether the element is editable | "true "; "false " |
contextmenu | HTML elements | The element's context menu | ID* |
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* |
crossorigin | audio ; img ; video | How the element handles crossorigin requests. | "anonymous "; "use-credentials " |
data | object | Address of the resource | Valid non-empty URL potentially surrounded by spaces |
datetime | del ; ins | Date and (optionally) time of the change | Valid date string with optional time |
datetime | time | Machine-readable value | Valid month string, valid date string, valid yearless date string, valid time string, valid local date and time string, valid time-zone offset string, valid global date and time string, valid week string, valid non-negative integer, or valid duration string |
default | track | Enable the track if no other text track is more suitable. | Boolean attribute |
defer | script | Defer script execution | Boolean attribute |
dir | HTML elements | The text directionality of the element | "ltr "; "rtl "; "auto " |
dirname | input ; textarea | Name of form field to use for sending the element's directionality in form submission | Text* |
disabled | button ; command ; fieldset ; input ; keygen ; optgroup ; option ; select ; textarea | Whether the form control is disabled | Boolean attribute |
draggable | HTML elements | Whether the element is draggable | "true "; "false " |
dropzone | HTML elements | Accepted item types for drag-and-drop | Unordered set of unique space-separated tokens, ASCII case-insensitive, consisting of accepted types and drag feedback* |
enctype | form | Form data set encoding type to use for form submission | "application/x-www-form-urlencoded "; "multipart/form-data "; "text/plain " |
for | label | Associate the label with form control | ID* |
for | output | Specifies controls from which the output was calculated | Unordered set of unique space-separated tokens, case-sensitive, 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 non-empty URL potentially surrounded by spaces |
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 " |
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, case-sensitive, consisting of IDs* |
height | canvas ; embed ; iframe ; img ; input ; object ; video | Vertical dimension | Valid non-negative integer |
hidden | HTML elements | Whether the element is relevant | Boolean attribute |
high | meter | Low limit of high range | Valid floating-point number* |
href | a ; area | Address of the hyperlink | Valid URL potentially surrounded by spaces |
href | link | Address of the hyperlink | Valid non-empty URL potentially surrounded by spaces |
href | base | Document base URL | Valid URL potentially surrounded by spaces |
hreflang | a ; area ; link | Language of the linked resource | Valid BCP 47 language tag |
http-equiv | meta | Pragma directive | Text* |
icon | command | Icon for the command | Valid non-empty URL potentially surrounded by spaces |
id | HTML elements | The element's ID | Text* |
inputmode | input ; textarea | Hint for selecting an input modality | verbatim ; latin ; latin-name ; latin-prose ; full-width-latin ; kana ; katakana ; numeric ; tel ; email ; url |
ismap | img | Whether the image is a server-side image map | Boolean attribute |
keytype | keygen | The type of cryptographic key to generate | Text* |
kind | track | The type of text track | "subtitles "; "captions "; "descriptions "; "chapters "; "metadata " |
label | command ; menu ; optgroup ; option ; track | User-visible label | Text |
lang | HTML elements | Language of the element | Valid BCP 47 language tag or the empty string |
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 non-empty URL potentially surrounded by spaces |
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 |
mediagroup | audio ; video | Groups media elements together with an implicit MediaController | Text |
method | form | HTTP method to use for form submission | "GET "; "POST "; |
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 |
muted | audio ; video | Whether to mute the media resource by default | 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 |
open | details | Whether the details are visible | Boolean attribute |
open | dialog | Whether the dialog box is showing | 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 |
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 non-empty URL potentially surrounded by spaces |
preload | audio ; video | Hints how much buffering the media resource will likely need | "none "; "metadata "; "auto " |
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 ; select ; 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, ASCII case-insensitive, consisting of "allow-forms ", "allow-pointer-lock ", "allow-popups ", "allow-same-origin ", "allow-scripts and "allow-top-navigation " |
spellcheck | HTML elements | Whether the element is to have its spelling and grammar checked | "true "; "false " |
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 ") | Unordered set of unique space-separated tokens, ASCII case-insensitive, consisting 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 ; track ; video | Address of the resource | Valid non-empty URL potentially surrounded by spaces |
srcdoc | iframe | A document to render in the iframe | The source of an iframe srcdoc document* |
srclang | track | Language of the text track | Valid BCP 47 language tag |
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 " |
style | HTML elements | Presentational and formatting instructions | CSS declarations* |
tabindex | HTML elements | Whether the element is focusable, and the relative order of the element for the purposes of sequential focus navigation | Valid integer |
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 |
title | HTML elements | Advisory information for the element | Text |
title | abbr ; dfn | Full term or expansion of abbreviation | Text |
title | command | Hint describing the command | Text |
title | link | Title of the link | Text |
title | link ; style | Alternative style sheet set name | Text |
translate | HTML elements | Whether the element is to be translated when the page is localized | "yes "; "no " |
type | a ; area ; link | Hint for the type of the referenced resource | Valid MIME type |
type | button | Type of button | "submit "; "reset "; "button " |
type | command | Type of command | "command "; "checkbox "; "radio " |
type | embed ; object ; script ; source ; style | Type of embedded resource | Valid MIME type |
type | input | Type of form control | input type keyword |
type | menu | Type of menu | "context "; "toolbar " |
typemustmatch | object | Whether the type attribute and the Content-Type value need to match for the resource to be used | Boolean attribute |
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 | data | Machine-readable value | 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 " |