data-*

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.

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.

Usage

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:

<img class="spaceship cruiserX3" src="shipX3.png"
  data-ship-id="324" data-weapons="laserI laserII" data-shields="72%"
  data-x="414354" data-y="85160" data-z="31940"
  onclick="spaceships[this.dataset.shipId].blasted()">

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

Specifications

Browser compatibility

See also

• All global attributes.
• The HTMLElement.dataset property that allows to access and modify these values.
• Using data attributes