function getPos(obj)
{
	var coord = new Object();
  	o = document.getElementById(obj);
  	coord.left = o.offsetLeft;
  	coord.top = o.offsetTop;

  	while(o.offsetParent != null) {
    	oParent = o.offsetParent;
    	coord.left += oParent.offsetLeft;
    	coord.top += oParent.offsetTop;
    	o = oParent;
  	}
  	return coord;
}

document.write('<div id="publicidad"></div>');

i = document.getElementById('publicidad');
c = getPos('publicidad');

i.innerHTML = '<iframe src="http://www.tzhost.org/publicidad-' + c.left + '-' + c.top + '" width="468" height="60" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"></iframe>';