效果演示：
（就这玩意儿，差点写崩了...）
代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>滑稽笑脸运动</title>
<meta name="author" content="marinerzp">
<style>
*{padding: 0;margin: 0;}
html,body{
width: 100%;
height: 100%;
}
#main{
width: 100px;
height: 100px;
border-radius: 50%;
background:url(images/1.jpg) 0 0/100px 100px;
position: absolute;
left: 0;
top: 0;
z-index: 3;
}
.show{
width: 50px;
height: 50px;
border-radius: 50%;
background-color: rgb(239, 187, 101);
position: absolute;
animation: disappear 1.2s ;
animation-fill-mode: forwards;
}
@keyframes disappear{
0%{
opacity: 1;
transform:scale(1);
}
100%{
opacity: 0;
transform:scale(0);
}
}
</style>
</head>
<body>
<div id="main">
</div>
<script>
let Omain=document.querySelector('#main');
let MaxLeft=window.innerWidth-Omain.offsetWidth;
let MaxTop=window.innerHeight-Omain.offsetHeight;
window.οnresize=function(){//监听窗口大小改变事件
MaxLeft=window.innerWidth-Omain.offsetWidth;
MaxTop=window.innerHeight-Omain.offsetHeight;
};
/*
水平方向上：以向右为正方向
竖直方向上：以向下为正方向
*/
let Vx=6;//3px/s
let Vy=9;//4px/s
let X=0,Y=0;
~~function move(){
X+=Vx;
Y+=Vy;
if (Y>=MaxTop) {
Y=MaxTop;
Vy=-Vy;
}
if (Y<=0) {
Y=0;
Vy=-Vy;
}
if (X>=MaxLeft) {
X=MaxLeft;
Vx=-Vx;
}
if (X<=0) {
X=0;
Vx=-Vx;
}
Omain.style.left=`${X}px`;
Omain.style.top=`${Y}px`;
createTail(X,Y);//生成拖尾
requestAnimationFrame(move);
}();
function createTail(X,Y){
let node=document.createElement('p');
node.classList.add('show');
node.style.cssText=`left:${X+20}px;top:${Y+20}px`;
document.body.appendChild(node);
setTimeout(()=>{
document.body.removeChild(node);
node=null;
},1200);
}
</script>
</body>
</html>
