how much mouse goes up and down at every moment
<p>how can I find out mouse position in browser ? I know <code>e.pageX , e.pageY</code> but i want to know mouse goes up or down and how much it goes (at every moment)? but i couldn't find a way to store last pageX,pageY to compare it with new pageX,pageY !</p>

<p>what i try to do is :</p>

<p>i have a picture that follows mouse. i want know how much mouse goes up or down so i can change picture size (if mouse goes up 5px my picture width will be +10px and if mouse goes down 5px my picture width will be -10px )</p>
