I'm looking to find a library that would allow me to use graphs as an input to HTML forms. To clarify:
The above was created using Chart.js and looks great, but I'm looking for something where the user would be able to drag each of the bars in the graph in order to select (in this case) the height of the lance at time t.
Does such a software/library exist for free?
I've managed to find a couple but they all cost quite a lot to buy.