Native to achieve a magnifying glass effect js

　We usually when electricity supplier shopping site, you need to select a certain commodity details view, will appear next to amplify the effect of one part of the picture during this time when the mouse to move a certain part of the picture viewed on a commodity, so it can be better the analysis of commodities, following on the use of native js to achieve a similar look magnifying glass effect.

Analysis of ideas:

　　1. mouse switching picture list, .pic box corresponding to the image switching

　　2. Generate in a .pic .zoom the box, similar to the .pic box moving pictures in the shear box

　　　　2.1 Dynamic property values acquired background-positin .zoom cassette box opposite .pic

　　　　2.2 .zoom limit the moving range of the box (box moves only .pic)

　　3. Cut the image scaled to display the box .details

NOTE: size enlargement scale = left box / boxes inside the shear size, the scale value display content as the right size of the box

Code is as follows :

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <meta name="viewport" content="width=device-width, initial-scale=1.0">
 6     <meta http-equiv="X-UA-Compatible" content="ie=edge">
 7     <title>原生js实现图片放大镜</title>
 8     <link rel="stylesheet" href="./css/style.css">
 9 </head>
10 
11 <body>
12 
13     <div id="wrap">
14         <div class="pic">
15             <img src="./images/1.jpg" alt="">
16             <div class="zoom"></div>
17         </div>
18         <ul class="list">
19             <li class="current">
20                 <img  src="./images/1.jpg" alt="">
21             </li>
22             <li>
23                 <img src="./images/2.jpg" alt="">
24             </li>
25             <li>
26                 <img src="./images/3.jpg" alt="">
27             </ <28>
             >
29                 <img src="./images/4.jpg" alt="">
30             </li>
31             <li>
32                 <img src="./images/5.jpg" alt="">
33             </li>
34             <li>
35                 <img src="./images/6.jpg" alt="">
36             </li>
37         </ul>
38         <div class="details"></div>
39 
40 
41     <script src="./js/index.js"></script>
42 </body>
43 </html>

HTML part

@charset "utf-8";

* {
    margin: 0;
    padding: 0;
}
li{
    list-style: none;
}

body {
    background-color: #eee;
}

#wrap {
    position: relative;
    width: 400px;
    height: 480px;
    margin: 50px auto;
    border: 1px solid #888;
}

#wrap .pic img {
    width: 400px;
    height: 400px;
}

#wrap .pic .zoom {
    position: absolute;
    top: 0;
    left: 0;
    width: 150px;
    height: 150px;
    background-color: lightblue;
    opacity: .4;
    cursor: move;
}

#wrap .list {
    display: flex;
    margin-top: 10px;
    justify-content: space-around;
}

#wrap .list li{
    cursor: pointer;    
}

#wrap .list .current{
    border: 2px solid red;
}

#wrap .list img {
    width: 50px;
    height: 50px;
    vertical-align: bottom;       /*Bottom blank solution image, change the alignment, the default baseline alignment * / 
} 

#wrap .details { 
    position : Absolute ;
     / * the display: none; * / 
    Top : 0 ; 
    left : 400px ; 
    width : 400px ; 
    height : 400px ; 
    margin -left : 20px ; 
    border : 1px Solid # 888 ; 
    background-Image : URL ( '/ Images / 1.jpg') ; 
    background-size : 266% ; 
}

CSS section

 1 var list = document.querySelector(' .list '),
 2     img = document.querySelector(' .pic img '),
 3     li_list = list.querySelectorAll(' li '),
 4     pic = document.querySelector(' #wrap .pic '),
 5     zoom = document.querySelector(' .zoom '),
 6     details = document.querySelector(' .details ')
 7 
 8 list.addEventListener('click', function (e) {
 9     e = e || window.event
10     // console.log(e.target)
11     if(e.target.tagName == 'the IMG' ) {
 12 is          img.src = e.target.src;
 13 is          details.style.backgroundImage = 'URL (' + + e.target.src ')' ;
 14          // Console .log (e.target.parentNode) 
15          li_list.forEach ( function (Item) {
 16              the console.log (Item)
 . 17              item.className = '';             // every six traversing element and li class name Clear 
18          })
 . 19          e.target.parentNode.className = 'Current';    // find e.target by adding the parent element and the class name 
20 is          // the console.log (li_list) 
21 is      }
22 is }, to false )
 23 is  
24 pic.addEventListener ( 'mouseMove', function (E) {
 25      E = E || the window.event
 26 is      var X = e.clientX,
 27          Y = e.clientY;
 28          CX = pic.getBoundingClientRect () .left;       //   getBoundingClientRect () Gets an element with respect to the set of windows 
29          CY = pic.getBoundingClientRect () Top;.
 30          TX = X - CX - 75 ;
 31 is          TY = Y - CY - 75 
 32          / / the console.log (E) 
33 is          //the console.log (X, Y) 
34 is          // the console.log (CX, CY) 
35  
36          // for limiting movement range .zoom cassette 
37 [          IF (TX <0 ) {             
 38 is              TX = 0 ;
 39          }
 40          IF (TX > 250 ) {
 41 is              TX 250 =
 42 is          }
 43 is          IF (TY <0 ) {
 44 is              TY = 0 ;
 45          }
 46 is          IF (TY> 250 ) {
 47               TY 250 =
 48          }
 49          
50         details.style.backgroundPosition = (tx / 250 * 100  + '%') + (ty / 250 * 100 + '%')
51         
52         zoom.style.left = tx + 'px'
53         zoom.style.top = ty + 'px';
54 })

js part

The net effect :

to sum up:

　　To achieve the overall effect of static, then code the logic step by step according to the needs, in order to achieve the overall effect

Native to achieve a magnifying glass effect js

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