js放大镜效果

在这里插入图片描述

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>放大镜</title>
        <style>
            *{
                padding: 0;
                margin: 0;
            }
            #small{
                width: 300px;
                height: 500px;
                position: absolute;
                left: 100px;
                top: 50px;
            }
            #small img{
                width: 100%;
                height: 100%;
            }
            #small span{
                display: block;
                width: 150px;
                height: 150px;
                background-color: black;
                opacity: .2;
                position: absolute;
                top: 0;
                left: 0;
                display: none;
            }
            #big{
                width:300px;
                height: 300px;
                display: none;
                position: absolute;
                left: 500px;
                top: 50px;
                overflow: hidden;
            }
            #big img{
                width: 600px;
                height: 1000px;
                position: absolute;

            }
        </style>
        <script>
            window.onload = function(){
                var oSmall = document.getElementById("small");
                var Simg = document.querySelector("#small img");
                var oSpan =document.querySelector("#small span");
                var oBig = document.getElementById("big");
                var Bimg = document.querySelector("#big img");
                oSmall.onmouseover = function(){
                    oSpan.style.display="block";
                    oBig.style.display="block";
                }
                oSmall.onmouseout = function(){
                    oSpan.style.display="none";
                    oBig.style.display="none";
                }
                oSmall.onmousemove = function(eve){
                    var e = eve ||window.event;
                    var l = e.clientX -oSmall.offsetLeft-75; 
                    var t = e.clientY -oSmall.offsetTop -75;
                    if(l<=0){
                        l=0;
                    }
                    if(l>150){
                        l=150;
                    }
                    if(t<=0){
                        t=0;
                    }
                    if(t>350){
                        t=350;
                    }
                    oSpan.style.left = l +"px";
                    oSpan.style.top =t +"px";
                    Bimg.style.left=-2*l+"px";
                    Bimg.style.top= -2*t +"px"
                }
            }
        </script>
    </head>
    <body>
        <div id="small">
            <img src="./timg.jpeg" alt="">
            <span></span>
        </div>
        <div id="big">
            <img src="./timg.jpeg" alt="">
        </div>
    </body>
    </html>
请用今天的努力,让明天没有遗憾。
原文地址:https://www.cnblogs.com/cupid10/p/15617745.html