Правильные координаты мыши в IE

isDOM=document.getElementById //DOM1 browser (MSIE 5+, Netscape 6, Opera 5+)
isOpera=isOpera5=window.opera && isDOM //Opera 5+
isOpera6=isOpera && window.print //Opera 6+
isOpera7=isOpera && document.readyState //Opera 7+
isMSIE=document.all && document.all.item && !isOpera //Microsoft Internet Explorer 4+
isMSIE5=isDOM && isMSIE //MSIE 5+
isNetscape4=document.layers //Netscape 4.*
isMozilla=isDOM && navigator.appName=="Netscape" //Mozilla или Netscape 6.*

mousex = 0
mousey = 0

if(isNetscape4) document.captureEvents(Event.MOUSEMOVE)
if(isMSIE || isOpera7){
  document.onmousemove=function(){
   mousex=event.clientX+document.body.scrollLeft;    
    mousey=event.clientY+document.body.scrollTop;
    return true
  }
}else if(isOpera){
  document.onmousemove=function(){
   mousex=event.clientX
    mousey=event.clientY
    return true
  }
}else if(isNetscape4 || isMozilla){
  document.onmousemove=function(e){
   mousex = e.pageX
    mousey = e.pageY
    return true
  }  
}