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HTML5 script element - async attribute - when (and how best) to use?



Can you confirm my understanding of HTML5's <script async> attribute?





  • Any libraries referenced by other code in the page should not specify the async attribute.







For example, my script references might appropriately look like:







<script src="jquery..." /> <!-- async not used - ensure that this is loaded before JQuery UI and my code -->

<script src="jquery.ui..." /> <!-- async not used - ensure that this is loaded before my code -->

<script src="my_code1.js" async /> <!-- async used, for page load performance -->

<script src="my_code2.js" async /> <!-- async used, for page load performance -->







  • For any code in a $(document).ready(function () { } block, I can be assured that all async script have already loaded.







Do I have this right?



Source: Tips4all

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