JS特效放大镜效果

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>放大镜效果</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .box {
            position: relative;
            margin: 100px 0;
            width: 450px;
            height: 450px;
            border: 1px solid #ccc;
        }
        
        .box .img {
            width: 100%;
            height: 100%;
        }
        
        .box .mask {
            display: none;
            position: absolute;
            width: 300px;
            height: 300px;
            left: 0;
            top: 0;
            background-color: rgb(231, 175, 20);
            opacity: .5;
            cursor: move;
        }
        
        .box .luper {
            display: none;
            position: absolute;
            top: -1px;
            left: 450px;
            width: 535px;
            height: 535px;
            z-index: 999;
            border: 1px solid #ccc;
            overflow: hidden;
        }
        
        .box .big {
            position: absolute;
            left: 0;
            top: 0;
        }
    </style>
    <script>
        window.addEventListener('load', function() {
            var box = document.querySelector('.box');
            var mask = document.getElementById('mask');
            var luper = document.querySelector('.luper');
            var big = document.querySelector('.big');
            // 当鼠标移进去时将隐藏的遮罩层显示出来
            box.addEventListener('mouseover', function(e) {
                this.style.crusor = 'move';
                mask.style.display = 'block';
                luper.style.display = 'block';
                // 当鼠标移动时将移动的位置赋予遮罩层
            });
            // 当我鼠标离开时就给我隐藏
            box.addEventListener('mouseout', function() {
                mask.style.display = 'none';
                luper.style.display = 'none';
            });
            // 当鼠标移动时赋予遮罩层的位置
            box.addEventListener('mousemove', function(e) {
                var x = e.pageX - this.offsetLeft;
                var y = e.pageY - this.offsetTop;
                maskX = x - mask.offsetWidth / 2;
                maskY = y - mask.offsetWidth / 2;
                // 左右移动最低为0最高为大盒子的宽度减去小盒子的宽度
                maskMaxWidth = box.offsetWidth - mask.offsetWidth;
                maskMaxHeight = box.offsetHeight - mask.offsetHeight;
                maskY = maskY < 0 ? 0 : maskY;
                maskX = maskX < 0 ? 0 : maskX;
                maskX = maskX > maskMaxWidth ? maskMaxWidth : maskX;
                maskY = maskY > maskMaxHeight ? maskMaxHeight : maskY
                mask.style.left = maskX + 'px';
                mask.style.top = maskY + 'px';
                // 打个鼠标移动时，右边的移动距离按比例放大
                // /大图片的移动距离=遮挡层移动距离*大图片最大移动距离/遮挡层的最大移动距离
                bigMax = big.offsetWidth - luper.offsetWidth;
                bigMaxY = big.offsetHeight - luper.offsetHeight;
                bigX = maskX * bigMax / maskMaxWidth;
                bigY = maskY * bigMaxY / maskMaxHeight;
                big.style.left = -bigX + 'px';
                big.style.top = -bigY + 'px';

            });
        });
    </script>
    <div class="box">
        <img src="images/cy2.jpg" alt="" class="img">
        <div class="mask" id="mask"></div>
        <div class="luper"><img src="images/cy2.jpg" alt="" class="big"></div>
    </div>
</head>

<body>

</body>

</html>
JS特效放大镜效果

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