<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
#div{width: 171px;height: 256px;padding: 5px;border: 1px solid #ccc;position: relative;}
#div .small{width: 171px;height: 256px;background: #eee;position: relative;}
#div .float{width: 50px;height: 50px;border: 1px solid #000;background: #fff;filter: alpha(opacity: 30);opacity: 0.3;position: absolute;top: 0;left: 0;display: none;}
#div .mark{width: 100%;height: 100%;position: absolute;z-index: 2;left: 0px;top: 0px;background: red;filter: alpha(opacity: 0);opacity: 0;}
#div .big{position: absolute;top: -1px;left: 215px;width: 171px;height: 256px;overflow: hidden;border: 2px solid #CCC;display: none;}
#div .big img {position: absolute;top: -30px;left: -80px;}
</style>
</head>
<body>
<!--用jquery面向对象写一个放大镜 -->
<!--注意：布局并设置好样式：大盒子div和小图盒子small为相对定位，遮罩mark滑块float大图盒子big大图图片均绝对定位，大图盒子big隐藏-->
<div id="div">
<div class="small">
<span class="mark"></span>
<span class="float"></span>
<img src="small.jpg" />
</div>
<div class="big">
<img src="big.jpg" />
</div>
</div>
<!--jquery-1.11.3.js文件下载到本地并导入该文件-->
<script src="jquery-1.11.3.js"></script>
<script>
//遮罩移入事件：滑块和大图盒子显示；遮罩移出事件：滑块和大图盒子隐藏;遮罩移动事件
$(function(){
$('.mark').mouseenter(function(){
$('.float').css({display: 'block'});
$('.big').css({display: 'block'});
}).mouseleave(function(){
$('.float').css({display: 'none'});
$('.big').css({display: 'none'});
}).mousemove(function(e){
//获取并设置滑块的位置
var left = e.offsetX - $('.float').width() / 2;
var top = e.offsetY - $('.float').height() / 2;
//设置滑块边界
if(left <= 0){
left = 0;
}else if(left >= $(this).outerWidth() - $('.float').outerWidth()){
left = $(this).outerWidth() - $('.float').outerWidth();
}
if(top <= 0){
top = 0;
}else if(top >= $(this).outerHeight() - $('.float').outerHeight()){
top = $(this).outerHeight() - $('.float').outerHeight();
}
$('.float').css({left:left + 'px',top:top + 'px'});
//设置滑块在遮罩上的移动比例(当前所在位置 /（遮罩的宽 -滑块的宽）)
var pX = left / ($(this).outerHeight() - $('.float').outerHeight());
var pY = top / ($(this).outerHeight() - $('.float').outerHeight());
//依据比例来设置大图图片显示的位置
var bigLeft = - pX * ($('.big img').outerWidth() - $('.big').outerWidth()) + 'px';
var bigTop = - pY * ($('.big img').outerHeight() - $('.big').outerHeight()) + 'px';
$('.big img').css({left:bigLeft,top:bigTop});
})
})
</script>
</body>
</html>