add external js html code example
Example 1: link javascript to html
<script src="index.js"> </script>Example 2: import script html
<html>
<head>
<script type="text/javascript" src="/path/to/script.js"></script>
...<script src="index.js"> </script><html>
<head>
<script type="text/javascript" src="/path/to/script.js"></script>
...