1 <!DOCTYPE html>
2 <html>
3 <head lang="en">
4 <meta charset="UTF-8">
5 <title></title>
6 </head>
7 <body>
8 <img src="imgA_1.jpg" id="img" alt=""/>
9 </body>
10 </html>
11 <script>
12 function myBrowser() {
13 var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串
14 var isOpera = userAgent.indexOf("Opera") > -1;
15 //判断是否Opera浏览器
16 if(isOpera) {
17 return "Opera";
18 }
19 //判断是否Firefox浏览器
20 if(userAgent.indexOf("Firefox") > -1) {
21 return "FF";
22 }
23 if(userAgent.indexOf("Chrome") > -1) {
24 return "Chrome";
25 }
26 if(userAgent.indexOf("Safari") > -1) {
27 return "Safari";
28 }
29 if(userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera) {
30 return "IE";
31 }
32 }
33
34
35 var i = document.getElementById("img");
36 if(myBrowser()=="ff"){
37 i.addEventListener("DOMMouseScroll",fun,false);
38 }else{
39 i.onmousewheel=fun;
40 }
41
42 function fun(e){
43 var ev=e||window.event;
44 var num=ev.wheelDelta||ev.detail;
45 if (num>0){ //正数表示滚轮向上,负数表示滚轮向下
46 i.style.width=i.offsetWidth*1.2+"px";
47 }else{
48 i.style.width=i.offsetWidth*0.8+"px";
49 }
50 }
51
52 </script>
