<!DOCTYPE html>
<html lang="zh">
<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>放大镜效果</title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
#main{
position: relative;
margin: 100px auto;
width: 1196px;
height: 496px;
border: 2px solid #ccc;
}
#small{
position: absolute;
width: 200px;
height: 200px;
top: 150px;
background-color: palegoldenrod;
}
#small img{
width: 200px;
height: 200px;
}
#big{
position: absolute;
width: 400px;
top: 50px;
left: 220px;
height: 400px;
display: none;
overflow: hidden;
}
#big img{
width: 700px;
height: 700px;
position: absolute;
}
#lucency{
position: absolute;
width: 100px;
top: 0px;
height: 100px;
background-color: yellow;
opacity: 0.5;
display: none;
}
</style>
</head>
<body>
<div id="main">
<div id="small">
<img src="img/shuju.jpg" />
<div id="lucency">
</div>
</div>
<div id="big">
<img src="img/shuju.jpg" class="bigImg" />
</div>
</div>
<script>
var small=document.getElementById('small'); //小盒子
var luncency=document.getElementById('lucency'); //黄色盒子
var big=document.getElementById('big');
var main=document.getElementById('main')
var bigImg=document.querySelector('.bigImg')
small.addEventListener('mouseover',function(){//鼠标放入预览图小盒子，大图和黄色显示
big.style.display='block';
luncency.style.display='block'
})
small.addEventListener('mouseout',function(){//鼠标离开预览图小盒子，大图和黄色隐藏
big.style.display='none';
luncency.style.display='none'
})
small.addEventListener('mousemove',function(e){
var smallLeft=e.pageX-main.offsetLeft //鼠标距离small左边的距离
var smallTop=e.pageY-main.offsetTop-small.offsetTop //鼠标距离small上边的距离
var smllle=smallLeft-luncency.offsetWidth/2
var smllto=smallTop-luncency.offsetHeight/2
var smllMax=small.offsetWidth-luncency.offsetWidth //遮挡层的最大移动距离
if(smllle<=0 ){
smllle=0
}else if(smllle>=smllMax){ //遮挡层的最大移动距离不能超出
smllle=100
}
if(smllto<=0){
smllto=0
}else if(smllto>=smllMax){
smllto=100
}
luncency.style.left=smllle+'px' //黄块跟着光标坐标走,黄块的左坐标
luncency.style.top=smllto+'px' //黄块跟着光标坐标走，黄块的纵坐标
//
var bigMax=big.offsetWidth-bigImg.offsetWidth //大图片的最大移动 距离
// 大图片的移动距离=遮挡层移动距离*大图片最大移动距离/遮挡层的最大移动距离
//大图片移动距离的x
var bigX=smllle*bigMax/smllMax;
//大图片移动距离的Y
var bigY=smllto*bigMax/smllMax;
bigImg.style.left=bigX+'px'
bigImg.style.top=bigY+'px'
})
</script>
</body>
</html>