Click to grab a point, move it to desired location, then click again to release it. You can also click on the fit line to add a control point.
This demo was built from an official Flot example found here, using my pchip-js fit library.
One of the goals of Flot is to support user interactions. Try pointing and clicking on the points.
Mouse hovers at (0, 0).
A tooltip is easy to build with a bit of jQuery code and the data returned from the plot.
Enable tooltip