Defer loading/parsing of Javascript

Rule from inspect under performance category

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By delaying when a Javascript file is loaded and parsed pages can be loaded and content shown, with the Javascript then following to provide extra functionality.

After loading, the parsing of Javascript is a heavy operation. Keeping the Javascript code of a web page small and only loading what's needed is a great way to reduce the performance hit browsers (and mostly mobile devices) take when hitting your page to render a basic layout.

How do I fix this ?

Move Javascript files to the end of your <body> tag, just before closing it </body> or mark Javascript files (that are not needed immediately to show the content of the page) with the attribute async as such:

<script src="/app.js" async></script>


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