 
<!DOCTYPE HTML> 
<html> 
<head> 
<meta charset="utf-8"> 
<title>放大鏡</title> 
<meta name="Keywords" content=""> 
<meta name="Description" content=""> 
<style type="text/css"> 
/*重置{*/ 
html{color:#000;background:#fff;} 
body,div{padding:0;margin:0;} 
img{border:none;} 
/*}重置*/ 
.outer{width:200px;height:150px;position:relative;margin:20px auto;} 
.inner{width:80px;height:60px;background:#f55;position:absolute;opacity:0.5;filter:alpha(opacity=50);left:0;top:0;cursor:pointer;} 
.aa{width:320px;height:240px;position:relative;border:1px red solid;margin:20px auto;overflow:hidden;} 
.imgs{position:absolute;} 
.outer img{width:200px;height:150px;} 
</style> 
</head> 
<body> 
<div> 
<div class="outer" id="outer"> 
<img src="images/pobabyb.gif" alt="pobaby小圖"/> 
<div class="inner" id="inner"></div> 
</div> 
<div class="aa" id="aa"> 
<div class="imgs" id="imgs" ><img src="images/pobabyb.gif" alt="pobaby大圖"/></div> 
</div> 
</div> 
<script type="text/javascript"> 
var outer=document.getElementById("outer"); 
var inner=document.getElementById("inner"); 
var aa=document.getElementById("aa"); 
var imgs=document.getElementById("imgs"); 
var x,y,n=false; 
inner.onmousedown=test1;//如果把inner改為document,鼠標(biāo)在窗口任意位置點擊，圖片都會跟隨 
document.onmousemove=test2;//document如果改為outer,鼠標(biāo)在outer內(nèi)才起作用 
document.onmouseup=test3; 
function test1(event){//鼠標(biāo)按下時方法 
var event=event || window.event;//調(diào)試兼容,各個瀏覽器認(rèn)識event有差別. 
n=true;//當(dāng)n=true（n的值可隨便設(shè)定）時，假定為鼠標(biāo)按下的事件 
x=event.clientX-inner.offsetLeft;//鼠標(biāo)在透明層的相對橫坐標(biāo)=鼠標(biāo)坐標(biāo)-方塊左邊距 
y=event.clientY-inner.offsetTop;//鼠標(biāo)在透明層的相對縱坐標(biāo)=鼠標(biāo)坐標(biāo)-方塊上邊距 
} 
function test2(event){//鼠標(biāo)移動時方法 
var event=event || window.event; 
if(n==true){ 
////////鼠標(biāo)移動范圍 
inner.style.left=event.clientX-x+"px"; 
inner.style.top=event.clientY-y+"px"; 
////////圖片移動范圍 
imgs.style.left=-4*parseInt(inner.style.left)+"px"; 
imgs.style.top=-4*parseInt(inner.style.top)+"px"; 
////////////////////////////限定鼠標(biāo)移動的范圍 
if(parseInt(inner.style.left)<0){ 
inner.style.left=0+"px"; 
} 
if(parseInt(inner.style.top)<0){ 
inner.style.top=0+"px"; 
} 
if(parseInt(inner.style.left)>outer.clientWidth-inner.clientWidth){ 
inner.style.left=outer.clientWidth-inner.clientWidth+"px"; 
} 
if(parseInt(inner.style.top)>outer.clientHeight-inner.clientHeight){ 
inner.style.top=outer.clientHeight-inner.clientHeight+"px"; 
} 
//////////////////////////////限定圖片移動的范圍 
if(parseInt(imgs.style.left)>0){ 
imgs.style.left=0+"px"; 
} 
if(parseInt(imgs.style.top)>0){ 
imgs.style.top=0+"px"; 
} 
if(parseInt(imgs.style.left)<-4*(outer.clientWidth-inner.clientWidth)){ 
imgs.style.left=-4*parseInt(outer.clientWidth-inner.clientWidth)+"px"; 
} 
if(parseInt(imgs.style.top)<-4*(outer.clientHeight-inner.clientHeight)){ 
imgs.style.top=-4*parseInt(outer.clientHeight-inner.clientHeight)+"px"; 
} 
} 
} 
function test3(){//鼠標(biāo)松開時方法 
n=false; 
} 
</script> 
</body> 
</html> 