link js file and html code example
Example 1: import js in html
<script type="text/javascript" src="yourfile.js"></script>
Example 2: how to reference a javascript file in html
<script type="text/javascript" src="path/filename.js"></script>
<script type="text/javascript" src="yourfile.js"></script>
<script type="text/javascript" src="path/filename.js"></script>