用vue对div进行上下左右移动

创建一个div，在div上按键盘中的上下左右，这个div会根据你所按的键盘来进行移动，每次移动10px，上哈左右，div会有四个颜色变化，div中的蚊子随着上下左右而变化，不能穿出图片超出弹出提示框


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>方向键移动div</title>
    <style>
        #box1 {
            width: 200px;
            height: 200px;
            background-color: aqua;
            position: absolute;
        }
    </style>
    <script>
        window.onload = function () {
            var b1 = document.getElementById("box1");
            var distance = 10;
            alert("按下ctrl键加速,按下alt键减速");
            document.onkeydown = function (event) {
                event = event || window.event;
                if (event.ctrlKey) {
                    distance = 40;
                }
                if (event.shiftKey) {
                    distance = 5;
                }
                if (event.keyCode === 37) {
                    b1.style.left = b1.offsetLeft - distance + "px";
                } else if (event.keyCode === 38) {
                    b1.style.top = b1.offsetTop - distance + "px";
                } else if (event.keyCode === 39) {
                    b1.style.left = b1.offsetLeft + distance + "px";
                } else if (event.keyCode === 40) {
                    b1.style.top = b1.offsetTop + distance + "px";
                }
            };
        };
    </script>
</head>
<body>
<div id="box1"></div>
</body>