html add js file to header code example
Example 1: import js in html
<script type="text/javascript" src="yourfile.js"></script>
Example 2: include script in html
<script type="text/javascript" src="/path/to/script.js"></script>
<script type="text/javascript" src="yourfile.js"></script>
<script type="text/javascript" src="/path/to/script.js"></script>