用JS写一个可以用键盘方向键控制的动画：
效果如下：
好了，代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
body {
overflow: hidden
}
img {
position: absolute;
top: 0;
left: 10px;
width: 100px;
height: 82px
}
.right {
transform: rotateY(180deg)
}
.top {
transform: rotateZ(45deg)
}
.bottom {
transform: rotateZ(-45deg)
}
</style>
</head>
<body>
<img src="./img//Blue ocean11.png" alt="" class="move-background">
<script>
var oImg = document.querySelector("img");
/* 思路： */
/* 监听键盘的事件(<- -> 上 下) */
document.onkeydown = function(e) {
e = e || window.event;
var code = e.which || e.keyCode;
var offset = 10;
switch (code) {
case 37:
console.log("left");
console.log('innerWidth',innerWidth,oImg.offsetLeft);
oImg.className = "";
var left = oImg.offsetLeft - offset;
if (left <= -oImg.offsetWidth) {
left = window.innerWidth;
}
oImg.style.left = left + "px";
break;
case 38:
console.log("top");
oImg.className = "top";
var top = oImg.offsetTop - offset;
if (top <= -oImg.offsetHeight) {
top = window.innerHeight;
}
oImg.style.top = top + "px";
break;
case 39:
console.log("right");
oImg.className = "right";
var left = oImg.offsetLeft + offset;
if (left >= window.innerWidth) {
left = -oImg.offsetWidth;
}
oImg.style.left = left + "px";
break;
case 40:
console.log("bottom");
oImg.className = "bottom";
var top = oImg.offsetTop + offset;
if (top >= window.innerHeight) {
top = -oImg.offsetHeight;
}
oImg.style.top = top + "px";
break;
default:
break;
}
/* 临界值检查 */
}
</script>
</body>
</html>
