前端JS电商放大镜效果：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>26-电商放大镜</title> <style type="text/css"> *{ padding: 0; margin: 0; } #left{ padding: 0; margin: 0; 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{ 200px; height: 200px; background: white; opacity: 0.6; position: absolute; top: 0; left: 0; display: none; box-sizing: border-box; } #cover{ 400px; height: 400px; background: red; position: absolute; left: 0; top: 0; opacity: 0; box-sizing: border-box; } #right{ 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 - 100; var box_top = mouse_top - 100; // 判断是否超出 if (box_left < 0) { box_left = 0; } if (box_left > 200) { box_left = 200; } if (box_top < 0) { box_top = 0; } if (box_top > 200) { box_top = 200; } // 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*-2; var rpic_top = box_top*-2; // 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>