HTML <nav> id Attribute

The id attribute on a <nav> tag assigns an identifier to the navigation section element. The identifier must be unique across the page.

Example

#

An id attribute on a <nav> element.

<nav id="nav-chapters">
  <a href="javascript:alert('Going to Introduction')">Introduction</a> <br />
  <a href="javascript:alert('Going to What Is HTML')">What is HTML</a>  <br />
  <a href="javascript:alert('Going to HTML Syntax')">HTML Syntax</a>  <br />
  <a href="javascript:alert('Going to HTML Elements')">HTML Elements</a>
</nav>

Using id

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

The identifier must be unique across the page.

The id allows programmatic access to the <nav> element.

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


Syntax

<nav id="identifier" />

Values

#

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

A <nav> element with a unique id.
Clicking the button will display the number of links inside the navigation element.


<nav id="mynav">
  <a href="javascript:alert('Going to Introduction')">Introduction</a> <br />
  <a href="javascript:alert('Going to What Is HTML')">What is HTML</a>  <br />
  <a href="javascript:alert('Going to HTML Syntax')">HTML Syntax</a>  <br />
  <a href="javascript:alert('Going to HTML Elements')">HTML Elements</a>
</nav>

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

<script>
  let show = () => {
    let element = document.getElementById("mynav");
    let length = element.getElementsByTagName("a").length;
    
    alert("Link count = " + length);
  }
</script>

Code explanation

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

Clicking the button calls JavaScript which locates the <nav> using the id.

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


Browser support

Here is when id support started for each browser:

Chrome
6.0 Sep 2010
Firefox
4.0 Mar 2011
IE/Edge
9.0 Mar 2011
Opera
11.0 Dec 2010
Safari
5.0 Jun 2010

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