[dheera]

I wrote FooPlot around the same time (2007). Ad revenue supplemented my PhD salary by quite a bit, though later on I couldn't keep up with Desmos as 1 person. The website's been down since AWS phased out EC2 classic instances and I was lazy to move it. But the code for the core library is still here, including the equation parsing which is quite similar to TFA. It's written in 2007-level JavaScript, so this could probably be a lot cleaner now.

https://github.com/dheera/fooplot

    git clone https://github.com/dheera/fooplot
    cd fooplot
    your-favorite-browser sample.html

It should support mouse panning and scroll wheel zooming.