Both 1st.js and 2nd.js scripts could be in one file named calcTaxes.js
There are NO HTML tags (like <script ...>) in that text file.
Should also be in the same directory unless you change the path.
OR Call as 2 separate <script type="text/JavaScript ... tags with the lower case "j" and "s"
Code:
<script type="text/javascript" src="calcTaxes.js"> </script>
<script type="text/javascript" src="calcGrossPay.js"> </script>
