The Choose a Spanking application is a "single page web application", implemented in JavaScript. The application is written to run in your browser, without any logic running on the web server.
The Choose a Spanking application does not maintain any state and, like the hotbottomstories.com web site, the application does not use "cookies" or track any user information.
The application uses the Bootstrap framework which supports display on a variety of devices.
You can see the JavaScript here. The JavaScript code is published under the Apache II software license