how to add js script in html code example
Example 1: import js in html
<script type="text/javascript" src="yourfile.js"></script>
Example 2: include js in html
<html>
<head>
</head>
<body>
<script type="text/javascript" src=es4.js></script>
</body>
</html>
Example 3: how to put javascript in HTML
<script>
//put your java script here
</script>