How to change the vibration intensity depending on the speed of the finger movement?

Question

JavaScript

Guys, I've been dumb for half an hour, I can't figure out how to do the following. Let's say I'm doing a drawing. I move my finger across the screen, a line is drawn. What event can draw this line after the finger?
Actually, I'm not doing a drawing. I need the intensity of the vibration to change with the speed of the finger. But I guess the principle is the same.
It's all about PhoneGap.
Thanks in advance for your replies.