DIV自动出滚动条

要用两个div配合实现

<div style="width:50px;height:20px;overflow-x:auto;overflow-y:hidden;">
    <div style="width:9999px;">
        <div>
            <img src="1.jpg">
            <span>图1</span>
        </div>
        <div>
            <img src="1.jpg">
            <span>图1</span>
        </div>
        <div>
            <img src="1.jpg">
            <span>图1</span>
        </div>
        <div>
            <img src="1.jpg">
            <span>图1</span>
        </div>
    </div>
<div>