mouse coordinates inside of one div displayed in another div - jquery

mouse coordinates inside of one div displayed in another div - jquery

So I have 2 divs:
<div class="ccc" style="position: relative; left: 100px; top: 50px; width:
200px; height: 150px; border: solid 1px;" oncontextmenu="return
false;"></div>
<div class="ddd" style="position: relative; left: 200px; top: 100px;
width: 100px; height: 40px; border: solid 1px;" oncontextmenu="return
false;"></div>
http://jsfiddle.net/n8rna/
And I need the following:
I need to track the mouse position / movement inside of the div with
class="ccc" (coordinates should be relative to this div, not to the page)
those coordinates needs to be displayed inside of the div with class="ddd"
if possible the coordinates should be registered at every 10th pixel
(10,10 - 20,10 etc instead of 1,1 - 2,1 - 3,1...)
I would prefer jquery function for this, but I am also open for other
approaches (javascript or something else).