The data-* global attributes form a class of attributes called custom data attributes, that allow proprietary information to be exchanged between the HTML and its DOM representation by scripts.

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All such custom data are available via the HTMLElement interface of the element the attribute is set on. The HTMLElement.dataset property gives access to them. The * may be replaced by any name following the production rule of XML names with the following restrictions:

  • The name must not start with xml (case-insensitive).
  • The name must not contain any colon characters (:).
  • The name must not contain any capital letters.

Note that the HTMLElement.dataset property is a DOMStringMap, and the name of the custom data attribute data-test-value will be accessible via HTMLElement.dataset.testValue (or by HTMLElement.dataset["testValue"]) as any dash (U+002D) is replaced by the capitalization of the next letter, converting the name to camelcase.


By adding data-* attributes, even ordinary HTML elements can become rather complex and powerful program-objects. For example, a space-ship "sprite" in a game could be a simple <img> element with a class attribute and several data-* attributes:

  class="spaceship cruiserX3"
  data-weapons="laserI laserII"
  onclick="spaceships[this.dataset.shipId].blasted()" />

For a more in-depth tutorial about using HTML data attributes, see Using data attributes.


HTML Standard
# attr-data-*

Browser compatibility

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See also