滑动滚轮放大缩小

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>标题</title>
<meta name="keywords" content="">
<meta name="description" content="">
<style>
    *{margin:0; padding:0; list-style:none;}
    body{
        height: 2000px;
    }
    #box{
        width: 200px;
        height: 200px;
        background: green;
    }
</style>
</head>
<body>
<div id="box"></div>
<script>
    var box=document.getElementById('box');
    var str=window.navigator.userAgent.toLowerCase();
    if (str.indexOf('firefox')!=-1) {//火狐浏览器
        box.addEventListener('DOMMouseScroll',function (event){
            // event.preventDefault();//阻止窗口默认的滚动事件
        // console.log(event.detail);//前滚-3
        if (event.detail<0) {
            console.log('前滚');
            box.style.width=box.offsetWidth+20+'px';
            box.style.height=box.offsetHeight+20+'px';
        };
        if (event.detail>0) {
            console.log('后滚');
            box.style.width=box.offsetWidth-20+'px';
            box.style.height=box.offsetHeight-20+'px';
        };
        return false;//阻止默认事件
        },false);
    } else{//非火狐浏览器
        box.onmousewheel=function (ev){
            var e=ev||window.event;
            /*if (e.preventDefault) {
                e.preventDefault();
            } else{
                e.returnValue=false;
            };*/
            // console.log(e);
            // console.log(e.wheelDelta);//前滚120
            if (e.wheelDelta>0) {
            console.log('前滚');
            box.style.width=box.offsetWidth+20+'px';
            box.style.height=box.offsetHeight+20+'px';
        };
        if (e.wheelDelta<0) {
            console.log('后滚');
            box.style.width=box.offsetWidth-20+'px';
            box.style.height=box.offsetHeight-20+'px';
        };
        return false;//阻止默认事件
        }
    };
    
</script>
</body>
</html>
原文地址:https://www.cnblogs.com/duenyang/p/5862797.html