Asynchronous and Deferred JavaScript Execution

There are two attributes for the <script> element which may be used to change the loading behavior. "async" to indicate that loading the script should not block the parser (e.g. may happen simultaneously) and "defer", which implies deferring the execution until the page has finished parsing.

The following list shows whether your browser implements these attributes by checking the presense of the JavaScript DOM properties, their behavior and order of precedence, as has been defined by the HTML5 Specification. This page contains some more info about the attributes.

  • async: Cannot run the test
  • defer: Cannot run the test

Red class means a test failed, where green text indicates that a text succeeded. JavaScript support is required to run this test.

This page is part of "???", published on 2010-09-13.