rem: return event.pageX || (event.clientX + 
add: return event.pageX || (event.clientX + 
context:   pointerX: function(event) {    return event.pageX || (event.clientX +       (document.documentElement.scrollLeft || document.body.scrollLeft));  },
meta: 3991	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/3991/d29159eae8749c508d01bb447868321a3ba6bbfa/prototype.js/buggy/manager/media/script/scriptaculous/prototype.js