HTML <ol> data-* Attribute

HTML <object>

HTML <optgroup>

A data-* attribute on an <ol> tag attaches additional data to the ordered list.

To create a custom attribute, replace * with a lowercase string, such as data-id, data-status, or data-location.

Example

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A custom data-title attribute on an ordered list.
The attribute value is not visible, but it is readable by JavaScript.

Amsterdam
London
Berlin
Paris

<ol data-title="List of location">
  <li>Amsterdam</li>
  <li>London</li>
  <li>Berlin</li>
  <li>Paris</li>
</ol>

Using data-*

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The data-* attribute adds custom information to an <ol> element.

The * part is replaced with a lowercase string, such as data-id, data-cost, or data-location.

An <ol> element can have any number of data-* attributes, each with their own name.

Using data-* attributes reduces the need for requests to the server.

Note: The data-* attribute is not visible and does not change the appearance of the ol.

Syntax

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<ol data-*="value">

Note: The * can be any string, such as data-id, data-cost, data-supplier, etc.

Values

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Value	Description
value	A string value. Can be numeric, alphanumeric, JSON, etc.

More Examples

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A custom data-content attribute on an <ol> element.
Clicking the button will display the content value.

Amsterdam
London
Berlin
Paris

<ol id="myol" data-content="List of cities">
  <li>Amsterdam</li>
  <li>London</li>
  <li>Berlin</li>
  <li>Paris</li>
</ol>

<br/>
<button onclick="show();">Show data</button>

<script>
  let show = () => {
    let element = document.getElementById("myol");
    alert("Content = " + element.getAttribute('data-content'));
  }
</script>

Code explanation

The <ol> tag has a custom data-content attribute.

The data-content attribute stores the content of the ordered list.

Clicks are handled by the onclick event.

Onclick invokes a JavaScript function that extracts and displays the <ol> content.

Note: Notice how the title displays immediately without server call.

Browser support

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Here is when data-* support started for each browser: