Check out example codes for "defer script html". It will help you in understanding the concepts better.

Code Example 1

<!--
  The defer attribute specifies that the script
  is executed when the page has finished parsing.
  
  Note: This only works for external scripts.
-->
<html>
  <head>
	<script defer type="text/javascript" src="/path/to/script.js"></script>
    ...

Code Example 2

<script src="demo_defer.js" defer></script>

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