...For schematics of how to connect to your MCU/MPU, see http://www.robots-everywhere.com/re_wiki/pub/web/Cookbook.AudioSerial.html
To add this library to your webpage, include this.
<script src='https://audioserial.sourceforge.io/serial-1.0.js'></script> or
<script src='http://audioserial.sourceforge.io/serial-1.0.js'></script>
To see a working demo, click here.
http://audioserial.sourceforge.io/serialdemo.html