求助：鼠标坐标不会随着移动刷新

for(var i=0;i<oImg.length;i++){
oImg[i].index=i;
oImg[i].onmouseover=function(event){
var event= event || window.event;
oSimg.src=(this.index+1)+".jpg";
oSimg.style.display='block';
oSimg.style.left = ((oSimg.offsetWidth+event.clientX) < document.documentElement.offsetWidth ? event.clientX+10:event.clientX-oSimg.offsetWidth-10)+"px";
oSimg.style.top=event.clientY+10+"px";
}
oImg[i].onmouseout=function(event){
oSimg.style.display="none";
}
}