Souřadnice javascript

function doSomething(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;

	}

        alert ('x=' + posx + " y=" + posy);

        document.write(posx + " " + posy) ; 

	// posx and posy contain the mouse position relative to the document

	// Do something with this information

}