I went to the HTML5 Developer Conference on Monday, and Ilya Grigorik’s (Software Engineering Manager, Google Analytics at Google) performance lecture was the highlight.
<script defer src=”script.js”></script>
If you use the defer attribute on several script tags, they will be loaded in they are included.
<script async src=”script.js”></script>
The defer attribute is supported by IE5.5+, FF3.5+, Chrome 8+, Safari 5+, iOS 5+ and Android 3+.
The async attribute is supported by IE10+, FF 3.6+, Chrome 8+, Safari 5+, iOS5+ and Android 3+.