if you can use jQuery, then this will help:
here is pure javascript only example:
var tempX = 0;
var tempY = 0;
function getMouseXY(e) {
if (IE) { // grab the x-y pos.s if browser is IE
tempX = event.clientX + document.body.scrollLeft;
tempY = event.clientY + document.body.scrollTop;
}
else { // grab the x-y pos.s if browser is NS
tempX = e.pageX;
tempY = e.pageY;
}
if (tempX < 0){tempX = 0;}
if (tempY < 0){tempY = 0;}
document.Show.MouseX.value = tempX;//MouseX is textbox
document.Show.MouseY.value = tempY;//MouseY is textbox
return true;
}