将光标更改为圆圈？

I'm building a website, and for part of it I have a whiteboard feature (which is basically a canvas). I'm trying to implement an eraser function for the whiteboard, and I wanted the cursor to change shape when the eraser is selected so that it matches the way in which the erasing is going to happen (at this point I'm trying to erase in a circle shape). So far I've tried this: I'm building a website, and for part of it I ha