var tt=document.getElementById("out");
var ff=document.getElementById("aa");
var wid=ff.offsetWidth/2;
var hei=ff.offsetHeight/2;
function move(e){
e=e||window.event;
m=mv(e);
ff.style.left=(m.x-wid)+"px";
ff.style.top=(m.y-hei)+"px";
function mv(e){
return {
x:e.clientX,
y:e.clientY
}
}
}
ff.onmousemove=move;
