简单的鼠标单机跟随

<script>
var img=document.getElementById("img");
var timer=null;
var leaderx=0;
var leadery=0;
var targetx=0;
var targety=0;
document.onclick=function(event){
var event=event||window.event;
var pagex=event.pageX||event.clientX+scroll().left;
var pagey=event.pageY||event.clientY+scroll().top;
targetx=pagex-img.offsetWidth/2;
targety=pagey-img.offsetHeight/2;
clearInterval(timer);

timer=setInterval(function(){

//缓速停止运动

var stepx=(targetx-leaderx)/10;
stepx=stepx>0?Math.ceil(stepx):Math.floor(stepx);
leaderx=leaderx+stepx;
var stepy=(targety-leadery)/10;
stepy=stepy>0?Math.ceil(stepy):Math.floor(stepy);
leadery=leadery+stepy;
img.style.left=leaderx+"px";
img.style.top=leadery+"px";
},10)
}


function scroll(){
if (window.pageYOffset!=null) {
return {
left:window.pageXOffset,
top:window.pageYOffset
}
}else if (document.compatMode==="CSS1Compat") {
return {
left:document.documentElement.scrollLeft,
top:document.documentElement.scrollTop
}
}return {
left:document.body.scrollLeft,
top:document.body.scrollTop
}
}
</script>