HTML <ol> id Attribute

An id on an <ol> tag assigns an identifier to the element.

The identifier must be unique across the page.



An id attribute on an <ol> element.

  1. Amsterdam
  2. London
  3. Berlin
  4. Paris
<ol id="locations">

Using id

The id attribute assigns an identifier to the <ol> element.

The id allows JavaScript to easily access the <ol> element.

It is also used to point to a specific id selector in a style sheet.

Tip:  id is a global attribute that can be applied to any HTML element.


<ol id="identifier" />



Value Description
identifier A unique alphanumeric string. The id value must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens (-), underscores (_), colons (:), and periods (.).

More Examples

An <ol> tag with a unique id.
Clicking the button displays the number of items inside the ordered list.

  1. Amsterdam
  2. London
  3. Berlin
  4. Paris

<ol id="myol">

<button onclick="show();">Show # cities</button>

  let show = () => {
    let element = document.getElementById("myol");
    let length = element.getElementsByTagName("li").length;
    alert("# Cities: " + length);

Code explanation

The id attribute assigns a unique identifier for the <ol>.

Clicking the button calls JavaScript that locates the <ol> through the id.

It then counts the number of <li> tags inside the <ol> and displays it in an alert box.

Browser support

Here is when id support started for each browser:

1.0 Sep 2008
1.0 Sep 2002
1.0 Aug 1995
1.0 Jan 2006
1.0 Jan 2003

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Last updated on Sep 30, 2023