Using JQuery mousemove to track mouse, Scrolling with wheel is fooling me

I'm noticing something very strange with Chrome/Ubuntu, seen also on the JQuery mousemove page here.

When I use the wheel to scroll vertically, I get new coordinates in pageX, pageY, but the pageY seems to be about 50px-60px off.

I can see 开发者_运维百科this because as soon as I move the mouse a little to the side, the Y coordinate suddenly jumps a lot.

Any ideas what I'm doing wrong, or how to get the "true" pageY coordinate?

Edit1: I now see that on windows I don't get mousemove events at all when scrolling with the wheel.

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• Binding to the window scroll event will fire when the mouse wheel is used
• Binding to mousemove event will fire when the mouse is moved

The coordinates are then calculated as follows:

PageX = ClientX + document.body.scrollLeft PageY = ClientY + document.body.scrollTop