implement javascript file in html code example
Example 1: include script in html
<script type="text/javascript" src="/path/to/script.js"></script>
Example 2: how to link your js file to html
<script src="index.js"></script>
Example 3: include js in html
<html>
<head>
</head>
<body>
<script type="text/javascript" src=es4.js></script>
</body>
</html>