Javascript - Finding that mouse position

I seem to constantly need this bit of code. Hope it helps someone else.

The following javascript code, finds the mouse position and returns it in an array.

function getMousePos(e) {
var posx = 0;
var posy = 0;
if (!e) var e = window.event;

if (e.pageX || e.pageY)
{
posx = e.pageX;
posy = e.pageY;
}
else if (e.clientX || e.clientY)
{
posx = e.clientX + document.body.scrollLeft
+ document.documentElement.scrollLeft;
posy = e.clientY + document.body.scrollTop
+ document.documentElement.scrollTop;
}
var out = new Array(2);
out[0] = posx;
out[1] = posy;
return out;
}

Demo - You can see it in action here.

Credits - I got the basics of this script from here.