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简单实现js放大镜效果

程序员文章站 2022-09-02 14:54:38
本文实例为大家分享了js放大镜效果展示的具体代码,供大家参考,具体内容如下 具体代码如下:

本文实例为大家分享了js放大镜效果展示的具体代码,供大家参考,具体内容如下

具体代码如下:

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>document</title>
  <style>
    body,div,img{
      margin:0;
      padding:0;
    }
    img{
      display:block;
      border:none;
    }
    #box{
      position:absolute;
      top:20px;
      left:20px;
      width:350px;
      height:350px;
      box-shadow:3px 3px 10px 0 #111111;

    }
    #box img{
      width:100%;
      height:100%;

    }
    #mark{
      display:none;
      position:absolute;
      top:0;
      left:0;
      width:175px;
      height:175px;
      background:#000;
      opacity: 0.5;
      filter:alpha(opacity=50);
      cursor:move;

    }
    #boxright{
      display:none;
      position:absolute;
      top:20px;
      left:380px;
      width:350px;
      height:350px;
      overflow:hidden;
    }
    /*我们右侧的图片的大小是需要严格计算的:
      mark的width是box的width的一半,那么我们的大图宽度也应该是小图的二倍
    */
    #boxright img{
      position:absolute;
      top:0;
      left:0;
      width:200%;
      height:200%;
    }
  </style>
</head>
<body>
  <div id='box'>
    <img src="img/iphone.jpg" alt="">
    <div id='mark'></div>
  </div>
  <div id='boxright'>
    <img src="img/iphone_big.jpg" alt="">
  </div>
  <script>
    //放大镜的原理: 我们的mark横向是box的一半,纵向也是box的一半,那么右侧的大图横向(纵向)应该是左侧小图的2倍
    var box = document.getelementbyid('box');
    var mark = document.getelementbyid('mark');
    var boxright = document.getelementbyid('boxright');
    //设置mark这个盒子
    function setposition(e){
      var top = e.clienty - box.offsettop - (mark.offsetheight/2);
      var left = e.clientx - box.offsetleft - (mark.offsetwidth/2);
      //边界判断
      var templ = 0,tempt = 0;
      var minl = 0,mint = 0,maxl = box.offsetwidth - mark.offsetwidth,maxt = box.offsetheight - mark.offsetheight ;

      if(left<minl){
        mark.style.left = minl + "px";
        templ = minl;
      }else if(left>maxl){
        mark.style.left = maxl + "px";
        templ = maxl;
      }else{
        mark.style.left = left + "px";
        templ = left;
      }
      if(top<mint){
        mark.style.top = mint + "px";
        tempt = mint;
      }else if(top>maxt){
        mark.style.top = maxt + "px";
        tempt = maxt;
      }else{
        mark.style.top = top + "px";
        tempt = top;
      }
      //右侧图片跟着运动:左侧移动多少,右侧跟着移动他的2倍即可
      var oimg = boxright.getelementsbytagname("img")[0];
      oimg.style.left = -templ*2 + "px";
      oimg.style.top = -tempt*2 + "px";

    }
    box.onmouseenter = function(e){
      e = e || window.event;
      
      mark.style.display = "block";
      setposition(e);
      boxright.style.display = "block";

    }
    box.onmousemove = function(e){
      e = e || window.event;
      setposition(e);

    }
    box.onmouseleave = function(e){
      e = e || window.event;
      mark.style.display = "none";
      boxright.style.display = "none";
      
    }
  </script>
</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。