How does this website's video tracker work?

You asked, so now we’ll explain how the video tracker built into this website works. It’s actually a nice example of what you can do with JavaScript and simple external interfaces. Credits: Talking: Geoffrey Challen (Assistant Professor, Computer Science and Engineering, University at Buffalo). Producing: Greg Bunyea (Undergraduate, Computer Science and Engineering, University at Buffalo). Part of the https://www.internet-class.org online internet course. A blue Systems Research Group (https://www.bluegroup.systems) production.