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

javascript html performance asynchronous google-analytics

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?

It's right on that page you linked to: "Firefox 3.6 is the first browser to officially offer support for this new feature" FWIW it's an HTML5 feature, which is quickly gaining better and better support.

The HTML5 spec says that async="true" is illegal. As a boolean HTML attribute, the presence of the attribute indicates "true", while the absence of the attribute equals "false". If the attribute is present, the only valid values for the attribute are "" and "async".

Here is a live test of this attribute html5demo.braincracking.org/demo/async.php.

This should be a bookmark to check frequently for anyone interested in this issue: en.wikipedia.org/wiki/Comparison_of_layout_engines_%28HTML5%29

Philip Rieck

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