注意：里边的两张图片(一大一小)可以自己添加，JQ采用jquery-1.11.3.js版，也可自行调换。
HTML代码：
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title>jQuery放大镜</title> <link rel="stylesheet" href="css/reset.min.css"/> <link rel="stylesheet" href="css/index.css"/> </head> <body> <div class="wrapper"> <div class="small"> <img src="img/1.jpg" alt=""/> <div class="mask"></div> </div> <div class="big"> <img src="img/2.jpg" alt=""/> </div> </div> <script src="js/jquery-1.11.3.js"></script> <script src="js/index.js"></script> </body> </html>
CSS代码：
@charset "UTF-8"; .wrapper{ width: 800px; margin: 50px auto; position: relative; } .wrapper .small{ position: absolute; top: 0; left: 0; width: 350px; height: 350px; border: 1px solid #000000; box-shadow: 3px 3px 5px #aaa; } .wrapper .small img{ width: 100%; height: 100%; } .wrapper .small .mask{ display: none; position: absolute; top: 0; left: 0; width: 150px; height: 150px; background-color: #000000; opacity: .4; cursor: move; } .wrapper .big{ display: none; position: absolute; overflow: hidden; top: 0; left: 355px; border: 1px solid #000000; box-shadow: 3px 3px 5px #aaa; } .wrapper .big img{ position: absolute; width: 800px; height: 800px; top: 0; left: 0; }
reset.min.css文件：
body,h1,h2,h3,h4,h5,h6,hr,p,blockquote,dl,dt,dd,ul,ol,li,button,input,textarea,th,td{margin:0;padding:0}body{font-size:12px;font-style:normal;font-family:"5FAE8F6F96C59ED1",Helvetica,sans-serif}small{font-size:12px}h1{font-size:18px}h2{font-size:16px}h3{font-size:14px}h4,h5,h6{font-size:100%}ul,ol{list-style:none}a{text-decoration:none;background-color:transparent}a:hover,a:active{outline-width:0;text-decoration:none}table{border-collapse:collapse;border-spacing:0}hr{border:0;height:1px}img{border-style:none}img:not([src]){display:none}svg:not(:root){overflow:hidden}html{-webkit-touch-callout:none;-webkit-text-size-adjust:100%}input,textarea,button,a{-webkit-tap-highlight-color:rgba(0,0,0,0)}article,aside,details,figcaption,figure,footer,header,main,menu,nav,section,summary{display:block}audio,canvas,progress,video{display:inline-block}audio:not([controls]),video:not([controls]){display:none;height:0}progress{vertical-align:baseline}mark{background-color:#ff0;color:#000}sub,sup{position:relative;font-size:75%;line-height:0;vertical-align:baseline}sub{bottom:-0.25em}sup{top:-0.5em}button,input,select,textarea{font-size:100%;outline:0}button,input{overflow:visible}button,select{text-transform:none}textarea{overflow:auto}button,html [type="button"],[type="reset"],[type="submit"]{-webkit-appearance:button}button::-moz-focus-inner,[type="button"]::-moz-focus-inner,[type="reset"]::-moz-focus-inner,[type="submit"]::-moz-focus-inner{border-style:none;padding:0}button:-moz-focusring,[type="button"]:-moz-focusring,[type="reset"]:-moz-focusring,[type="submit"]:-moz-focusring{outline:1px dotted ButtonText}[type="checkbox"],[type="radio"]{box-sizing:border-box;padding:0}[type="number"]::-webkit-inner-spin-button,[type="number"]::-webkit-outer-spin-button{height:auto}[type="search"]{-webkit-appearance:textfield;outline-offset:-2px}[type="search"]::-webkit-search-cancel-button,[type="search"]::-webkit-search-decoration{-webkit-appearance:none}::-webkit-input-placeholder{color:inherit;opacity:.54}::-webkit-file-upload-button{-webkit-appearance:button;font:inherit}.clear:after{display:block;height:0;content:"";clear:both}
JS代码：
/** * Created by 35107 on 2017/5/8. */ $(function () { var smallL, smallT, minL = 0, minT = 0, maxL, maxT; var $wrapper = $('.wrapper'), $small = $wrapper.children('.small'), $mask = $small.children('.mask'), $big = $wrapper.children('.big'), $curImg = $small.children('img'), $bigImg = $big.children('img'); var multiple = 2 / 3, n = null, maskW = $curImg.width() * multiple, maskH = $curImg.height() * multiple, bigW = $bigImg.width() * multiple, bigH = $bigImg.width() * multiple; $mask.css({ maskW, height: maskH}); $big.css({ bigW, height: bigH}); $small.on({ mouseenter: function (e) { $mask.css('display', 'block'); $big.css('display', 'block'); setPos(e); }, mousemove: function (e) { setPos(e); }, mouseleave: function () { $mask.css('display', 'none'); $big.css('display', 'none'); } }); function setPos(e) { if (!smallL) { smallL = $small.offset().left; smallT = $small.offset().top; maxL = $small.innerWidth() - maskW; maxT = $small.innerHeight() - maskW; n = ($bigImg.width() - bigW ) / maxL; } var curL = e.clientX - smallL - maskW / 2, curT = e.clientY - smallT - maskH / 2; curL = curL < minL ? minL : (curL > maxL ? maxL : curL); curT = curT < minT ? minT : (curT > maxT ? maxT : curT); $mask.css({left: curL, top: curT}); $bigImg.css({left: -curL * n, top: -curT * n}) } function calculatedWidth() { } });