Defer loading of js how?

javascript html pagespeed google-pagespeed
Kermit the Frog picture Kermit the Frog · Nov 19, 2013 · Viewed 11.6k times · Source

I have the following js script referenced on the bottom of the page:

<script src="http://example.com/test.js" type="text/javascript"></script>

Google PageSpeed suggestion is to defer the loading of this js. I don't quite understand how to do that or the repercussions. Can someone please explain?

Answer

pilsetnieks picture pilsetnieks · Nov 19, 2013

Adding the attribute defer to the <script> tag should do it. E.g.:

<script src="http://example.com/test.js" type="text/javascript" defer></script>

The idea is that the script in the file is executed only after the whole page has finished loading, as opposed to the standard way when the script is executed as soon as the browser parses the <script> tag (which may delay rendering of the code after the <script> tag.)

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