HTML <nav> id Attribute

HTML <meter>

HTML <noscript>

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

The identifier must be unique across the page.

Example

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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

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

The id allows JavaScript to easily access the <nav> 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.

Syntax

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<nav id="identifier" />

Values

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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

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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

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Here is when id support started for each browser: