Which browsers support <script async="async" />?

asynchronous, google-analytics, html, javascript, performance

Solution

The async support as specified by google is achieved using two parts:

using script on your page (the script is supplied by google) to write out a <script> tag to the DOM.

that script has async="true" attribute to signal to compatible browsers that it can continue rendering the page.

The first part works on browsers without support for `<script async..` tags, allowing them to load async with a "hack" (although a pretty solid one), and also allows rendering the page without waiting for ga.js to be retrieved.

The second part only affects compatible browsers that understand the async html attribute

- FF 3.6+

- FF for Android All Versions

- IE 10+ (starting with preview 2)

- Chrome 8+

- Chrome For Android All versions

- Safari 5.0+

- iOS Safari 5.0+

- Android Browser 3.0+ (honeycomb on up)

- Opera 15.0+

- Opera Mobile 16.0+

- Opera Mini None (as of 8.0)

The "html5 proper" way to specify async is with a `<script async src="..."`, not `<script async="true"`. However, initially browsers did not support this syntax, nor did they support setting the script property on referenced elements. If you want this, the list changes:

- FF 4+

- IE 10+ (preview 2 and up)

- Chrome 12+

- Chrome For Android 32+

- Safari 5.1+

- No android versions

Problem

On December 1, 2009, Google announced support for asynchronous Google Analytics tracking. The asynchronous tracking is achieved using the async directive for the `<script>` tag. Which browsers support the async directive (`<script async="async" />`) and since which version?

Original source