HTML5 data-* attributes provide a convenient way to store data in HTML elements. The stored data can be read or modified using JavaScript

<div data-submitted="yes" class="user_profile">
  … some content …
</div>

• Data attribute structure is data-*, i.e. the name of the data attribute comes after the data- part. Using this name, the attribute can be accessed.
• Data in string format (including json) can be stored using data-* attribute.