get mouse position javascript

                                    <p>Click in the div element below to get the x (horizontal) and y (vertical) coordinates of the mouse pointer, when it is clicked.</p>

<div onclick="showCoords(event)"><p id="demo"></p></div>

<p><strong>Tip:</strong> Try to click different places in the div.</p>

<script>
function showCoords(event) {
  var cX = event.clientX;
  var sX = event.screenX;
  var cY = event.clientY;
  var sY = event.screenY;
  var coords1 = "client - X: " + cX + ", Y coords: " + cY;
  var coords2 = "screen - X: " + sX + ", Y coords: " + sY;
  document.getElementById("demo").innerHTML = coords1 + "<br>" + coords2;
}
</script>

                                    (function() {
    document.onmousemove = handleMouseMove;
    function handleMouseMove(event) {
        var eventDoc, doc, body;

        event = event || window.event; // IE-ism

        // If pageX/Y aren't available and clientX/Y are,
        // calculate pageX/Y - logic taken from jQuery.
        // (This is to support old IE)
        if (event.pageX == null && event.clientX != null) {
            eventDoc = (event.target && event.target.ownerDocument) || document;
            doc = eventDoc.documentElement;
            body = eventDoc.body;

            event.pageX = event.clientX +
              (doc && doc.scrollLeft || body && body.scrollLeft || 0) -
              (doc && doc.clientLeft || body && body.clientLeft || 0);
            event.pageY = event.clientY +
              (doc && doc.scrollTop  || body && body.scrollTop  || 0) -
              (doc && doc.clientTop  || body && body.clientTop  || 0 );
        }

        // Use event.pageX / event.pageY here
    }
})();