用javascript制作放大镜放大图片

<html> 
<head> 
<title>emu</title> 
</head> 
<body> 
<BR> 
原图:<BR> 
<img src=http://www.web745.com/image/logo.gif width="280" height="150" id=srcImg onmousemove="zoom()"> 
<BR> 
局部放大图:<BR> 
<div style="overflow:hidden"><img id=zoomImg></div> 

<SCRIPT LANGUAGE="JavaScript"> 
<!-- 
zoomImg.src = srcImg.src; 
srcImg.height = srcImg.height/2; 
var zoomRate = 5; //放大倍数 
zoomImg.height = srcImg.height*zoomRate; 
zoomImg.parentNode.style.width = srcImg.width; 
zoomImg.parentNode.style.height = srcImg.height; 
function zoom(){ 
var elm = event.srcElement; 
h = elm.offsetHeight/zoomRate/2; 
w = elm.offsetWidth/zoomRate/2; 
var x = event.x-elm.offsetLeft; 
x=x<(elm.offsetWidth-w)?x<w?w:x:elm.offsetWidth-w; 
zoomImg.style.marginLeft=(w-x)*zoomRate; 
var y = event.y-elm.offsetTop; 
y=y<(elm.offsetHeight-h)?y<h?h:y:elm.offsetHeight-h; 
zoomImg.style.marginTop=(h-y)*zoomRate; 

//--> 
</SCRIPT> 
</body> 
</html> 
 
原文地址:https://www.cnblogs.com/MaxIE/p/549289.html