How do I defer parsing of Javascript to iprove performace

Please make this post a private. Thank you.

I ran GT matrix on my site and one of the recommendations is to Defer parsing of JavaScript (See below) -

How do I go about this as I don't understand what it means?



F (45)
JS High
What does this mean?
323.5KiB of JavaScript is parsed during initial page load. Defer parsing JavaScript to reduce blocking of page rendering. (126.4KiB) (83.7KiB) (43.3KiB) (21.5KiB of inline JavaScript) (12.8KiB) (11.2KiB of inline JavaScript) (5.5KiB)