demo 点击图片当前显示变大，其他变小

<style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 1000px;
            margin: 50px auto;
            overflow: hidden;
        }
        .box ul{
            list-style: none;
            width: 4000px;
        }
        .box li{
            float: left;
            width: 200px;
        }
    </style>

<div class="box" id="box">
    <ul id="ul">
        <li>![](images/0.large.JPG)</li>
        <li>![](images/1.large.jpg)</li>
        <li>![](images/2.large.jpg)</li>
        <li>![](images/3.large.JPG)</li>
        <li>![](images/4.large.JPG)</li>
    </ul>
</div>

<script src="JavaScript/base.js"></script>   //  详情 animate() 封装
<script>
    var box = document.getElementById("box");
    var ul = document.getElementById("ul");
    var lis = ul.children;

    for(var i = 0;i<lis.length;i++){
        lis[i].onmouseover = function(){
            for(var j = 0;j<lis.length;j++){
                animate(lis[j],{width:100})
            }
            animate(this,{width:600})
        };
        lis[i].onmouseout = function(){
            for(var j = 0;j<lis.length;j++){
                animate(lis[j],{width:200})
            }
        }
    }

</script>