Load ad tag asynchronously

  • This audit verifies if ad tag library scripts are loaded asynchronously to improve page performance.

  • Asynchronous loading allows the browser to load other content while the script loads in the background, preventing delays and improving user experience.

  • To enable asynchronous loading, include the async attribute within the <script> tag when implementing ad tags like AdSense and Google Publisher Tag.

  • Synchronous loading, where the browser waits for the script to fully load before proceeding, can negatively impact page load times and overall performance.

Overview

This audit ensures ad tag library scripts are loaded asynchronously.

By default, JavaScript execution is synchronous. This means that once a script is encountered, no other content can be loaded until that script has been downloaded, parsed, and executed. Opting into asynchronous execution prevents this, allowing the browser to continue processing other resources while the specified script is loaded in the background. This keeps your page responsive while scripts are loading and decreses the time necessary to load all critical components.

Recommendations

Include the async attribute in the script tag definition. For example:

AdSense

<script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

AdSense (auto ads)

<script async data-ad-client="ca-pub-xxxxxxxxxxxxxxxx" src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>

Google Publisher Tag

<script async src="https://securepubads.g.doubleclick.net/tag/js/gpt.js"></script>

More information

The following ad tag library scripts are supported:

Ad Tag Library Script(s)
AdSense

pagead2.googlesyndication.com/pagead/js/adsbygoogle.js

pagead2.googlesyndication.com/pagead/show_ads.js
Google Publisher Tag

googletagservices.com/tag/js/gpt.js

securepubads.g.doubleclick.net/tag/js/gpt.js

Get Started with Google Publisher Tags
GPT request modes and asynchronous rendering