[jodrellblank]

You load the web page on your phone, put it in to the microwave and close the door. The microwave should be a Faraday cage preventing microwave radiation getting through. Now the phone/web page cannot contact the internet. The chart stops updating.

Unless there's a leak, then the chart continues updating while the phone is in the microwave.

Then open the door and look if it could/couldn't keep pinging the server while the door was closed.

[FredPret]

I did this and now my phone has an extra 4gb of RAM

[dankle]

Mine has 5G now!

[bitcharmer]

This doesn't answer GP's question. How does it work? Why does my workstation connected to my router via ethernet cable show wildly varying results? What is the unit of Y axis?

[tgsovlerkhgsel]

Seconds (judging by the source code), and I assume the variance comes from the time it takes the server to respond + javascript delays. It's interesting to see the significant variation and an almost 100 ms difference between what my browser reports and what the chart reports. (The server responses were pretty consistent).