通过鼠标中间滚轮来缩放图片大小
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default12.aspx.cs" Inherits="Default12" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title>无标题页</title></head><body> <form id="form1" runat="server"> <img onmousewheel="return bbimg(this)" src="images/__scale__1_227959004.gif" /> <span style="font-weight: bold">Size = <span id="oCounter" style="color: red;">100%</span></span> <img id="oImage" src="images/__scale__1_227959004.gif" onmousewheel="return Picture();" /> </form></body></html><script language="JavaScript" type="text/javascript"> 
function bbimg(o){
var zoom=parseInt(o.style.zoom,10)||100;zoom+=event.wheelDelta/12;if(zoom>0) o.style.zoom=zoom+'%';
return false;} var count = 10; function Picture() { count = Counting(count); Resize(count); return false; } function Counting(count){ if (event.wheelDelta >= 120) count++; else if (event.wheelDelta <= -120) count--; return count; } function Resize(count){ if (count >=1){document.getElementById("oImage").style.zoom = count + '0%'; oCounter.innerText = count + '0%'; }
} </script>
