how to call a js file from another js file on click code example

Example 1: include other js files in a js file

document.writeln("<script type='text/javascript' src='Script1.js'></script>");
document.writeln("<script type='text/javascript' src='Script2.js'></script>");

Example 2: how to call a script from another script in javascript

<script type="text/javascript" src="file1.js"></script>
<script type="text/javascript" src="file2.js"></script>
<script type="text/javascript">
    alertOne( );
</script>