<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.box{
width: 400px;
height: 400px;
border: 2px solid #ccc;
position: absolute;
left: 0;
top: 0;
}
.box img{
width: 400px;
height: 400px;
}
.nas{
width: 200px;
height: 200px;
border: 2px solid #ccc;
position: absolute;
left: 0;
top: 0;
}
.work{
width: 400px;
height: 400px;
border: 2px solid #000;
position: absolute;
overflow: hidden;
left: 500px;
top: 0;
}
.work img{
width: 800px;
height: 800px;
position: absolute;
left: 0;
top: 0;
}
</style>
</head>
<body>
<div class="box">
<img src="img/2.jpg" >
<div class="nas">
</div>
</div>
<div class="work">
<img src="img/2.jpg" >
</div>
</body>
<script>
// 获取元素
var nas=document.querySelector(".nas");
var box=document.querySelector(".box");
var work=document.querySelector(".work");
var img=document.querySelector( ".work img")
// 绑定点击事件
nas.onmousedown=function(even){
var even=even||window.event;
var oLeft=even.offsetX;
var oTop=even.offsetY;
var r=(box.clientHeight-nas.clientHeight)/(500-img.clientLeft-work.clientLeft);
console.log(r);
document.onmousemove=function(eve){
var e=eve||window.event;
var x =e.clientX-oLeft ;
var y=e.clientY-oTop
// 判断是否到边界
// 左右判定
if(x<=0){
x=0;
}else if(x>box.clientWidth-nas.clientWidth){
x=box.clientWidth-nas.clientWidth;
}
// 上下判定
if(y<=0){
y=0;
}else if(y>box.clientHeight-nas.clientHeight){
y=box.clientHeight-nas.clientHeight;
}
nas.style.left=x+"px";
nas.style.top=y+"px";
img.style.left=-(x/r)+"px";
img.style.top=-(y/r)+"px";
}
}
// 鼠标抬起的时候清
nas.onmouseup=function(){
document.onmousemove=null;
}
</script>
</html>
Effect picture
