对联悬浮框原生js写法

还是直接上代码比较实在

html:

<img src =""  id="erwei" >

css:

body{

height:5000px

}

#erwei{

position:absolute;

right:30px;

}

js:

vardiv=document.getElementById('erwei')

window.onscroll=function() {

//兼容

varscrollTop=document.documentElement.scrollTop||document.body.scrollTop;

Move(parseInt((document.documentElement.clientHeight-div.offsetHeight) /2+scrollTop))

}

vartimer

function Move(target) {

clearInterval(timer)

timer=setInterval(function() {

varspeed= (target-div.offsetTop)/4;

speed=speed>0?Math.ceil(speed):Math.floor(speed);

if(div.offsetTop==target) {

clearInterval(timer)

}else{

div.style.top=div.offsetTop+speed+'px';

}

},30)

}