WebIO / PlotlyJS click event coordinates

I need to get the x,y coordinates of the cursor during a click event.

The following example returns the location of the nearest point (based on the x-coordinates), so it must be using the cursor location somewhere, but I don’t see a good way to grab it.

using PlotlyJS
using WebIO

P = plot(rand(10, 4))
on(P["click"]) do data