References

Beginner-friendly references for web development, with live, editable examples.

The HTML nomodule attribute

Attribute All modern browsers Updated
Quick answer

The HTML nomodule attribute marks a script to be ignored by browsers that support ES modules. It is used on the <script> element.

Overview

The nomodule attribute marks a script to be ignored by browsers that support ES modules. It applies to the <script> element.

It is the classic module/nomodule pattern: ship <script type="module"> for modern browsers and <script nomodule> as a fallback. In 2026 it is rarely needed, since virtually all browsers support modules.

Syntax

<script nomodule src="legacy.js"></script>

Values

Value
A boolean attribute — present or absent.

Best practices

  • Declare the character encoding with <meta charset="utf-8"> first in the <head>.
  • Load scripts with defer (or as modules) so they do not block parsing.
  • Protect third-party resources with integrity and crossorigin (Subresource Integrity).
  • Use resource hints like preload deliberately, paired with the right as value.

Frequently asked questions

What does the nomodule attribute do?
Provides a fallback script for legacy browsers.
Where do head attributes apply?
On the metadata elements in the <head> — <meta>, <link>, <script> and <base>.
What is the difference between async and defer?
async runs a script as soon as it loads in no set order; defer runs scripts in order after the document is parsed.
Which elements use the nomodule attribute?
It is an element-specific attribute, used on document head elements like <meta>, <link> and <script>.
name (meta) novalidate