Importuj JS w HTML
<script type="text/javascript" src="yourfile.js"></script>
SteDeus
<script type="text/javascript" src="yourfile.js"></script>
<script src="index.js"></script>
<script src="Your-JavaScript-File.js"></script> <!--If JS file is in same folder with HTML file-->
<html>
<head>
<script type="text/javascript" src="/path/to/script.js"></script>
...