JS实现电商放大镜效果

前端JS电商放大镜效果，供大家参考，具体内容如下

<!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;
    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: 0;
    left: 0;
    display: none;
  box-sizing: border-box;
  }
  #cover{
    width: 400px;
    height: 400px;
    background: red;
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
  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 - 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>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。