前端JS电商放大镜效果 | 前端JS电商放大镜效果

前端JS电商放大镜效果：
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>-电商放大镜</title>

    <style type="text/css">

    *{

        padding: ;

        margin: ;

    }

    #left{

      padding: ;

    margin: ;

        width: 400px;

        height: 400px;

        border: 2px solid blue;

        background: url(http://chuantu.biz/t6/17/1503469475x2063891122.jpg) no-repeat;

        float: left;

        cursor: crosshair;

        position: relative;

    box-sizing: border-box;

    }

    #box{

        width: 200px;

        height: 200px;

        background: white;

        opacity: 0.6;

        position: absolute;

        top: ;

        left: ;

        display: none;

    box-sizing: border-box;

    }

    #cover{

        width: 400px;

        height: 400px;

        background: red;

        position: absolute;

        left: ;

        top: ;

        opacity: ;

    box-sizing: border-box;

    }

    #right{

        width: 400px;

        height: 400px;

        border: 2px solid black;

        overflow: hidden;

        position: relative;

        display: none;

    box-sizing: border-box;

    }

    #rpic{

        position: absolute;

    }

    </style>

    <script type="text/javascript">

    window.onload = function(){

        var left = document.getElementById("left");

        var right = document.getElementById("right");

        var rpic = document.getElementById("rpic");

        var box = document.getElementById("box");

        var cover = document.getElementById("cover");

        // 给左侧加鼠标移动事件

        cover.onmousemove = function(){

            //获得事件对象

            var ev = window.event;

            var mouse_left = ev.offsetX || ev.layerX;

            var mouse_top = ev.offsetY || ev.layerY;

            // document.title = mouse_left + '|' +  mouse_top;

            //计算色块的位置

            var box_left = mouse_left - ;

            var box_top = mouse_top - ;

            // 判断是否超出

            if (box_left < ) {

                box_left = ;

            }

            if (box_left > ) {

                box_left = ;

            }

            if (box_top < ) {

                box_top = ;

            }

            if (box_top > ) {

                box_top = ;

            }

            // 让色块移动

            box.style.left = box_left + 'px';

            box.style.top = box_top + 'px';

            //计算右侧图片位置

            var rpic_left = box_left*-;

            var rpic_top = box_top*-;

            // 让右侧移动

            rpic.style.left = rpic_left + 'px';

            rpic.style.top = rpic_top + 'px';

        }

            //给左侧加鼠标移入事件

            cover.onmouseover = function(){

                // 让左侧色块和右侧隐藏

                box.style.display = 'block';

                right.style.display = 'block';

            }

            // 给左侧加鼠标移出事件

            cover.onmouseout = function(){

                // 让左侧色块和右侧隐藏

                box.style.display = 'none';

                right.style.display = 'none';

            }

    }

    </script>

</head>

<body>

    <div id="left">

        <div id="box"></div>

        <div id="cover"></div>

    </div>

    <div id="right">

        <img src="http://chuantu.biz/t6/17/1503469419x2063891122.jpg" id="rpic">

    </div>

</body>

</html>