How to implement cropping a photo with a choice of a place in a photo?

Question

JavaScript

I want, as in the social. networks, crop photos and choose an avatar.
That is, the user selects a photo, points to areas, then the photo is loaded and the server crops the photo, making a reduced photo, say 50 * 50 px and a little more - 100 * 100 from the area that the user specified.
How to implement this?

Answer 1

use canvas

Answer 2

he knows