js实现无缝循环滚动

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>无缝滚动</title>
</head>
<style type="text/css">
    .row{
        width: 1298px;
        height: 400px;
        border: 1px solid;
        box-shadow:2px 2px 2px #000;
        overflow: hidden;
    }
    .box{
        position: relative;
    }
    .box1,.box2{
        width: 1298px;
        position: absolute;
    }
    .box2{
        left:1298px;
    }
    img{
        float: left;
    }
</style>
<body>
    <div class="row">
        <div class="box" id="box">
            <div class="box1" id="box1">
                <img src="images/1.jpg">
                <img src="images/2.jpg">
                <img src="images/3.jpg">
                <img src="images/4.jpg">
                <img src="images/5.jpg">
            </div>
            <div class="box2" id="box2">
                <img src="images/1.jpg">
                <img src="images/2.jpg">
                <img src="images/3.jpg">
                <img src="images/4.jpg">
                <img src="images/5.jpg">
            </div>
        </div>
    </div>
</body>
<script type="text/javascript">
    window.onload = function(){
        var _box1 = document.getElementById("box1");
        var _box2 = document.getElementById("box2");
        var x = 0;
        var fun = function(){
            _box1.style.left = x + 'px';
            _box2.style.left = (x +1298) + 'px';
            x--;
            if((x +1298) == 0){
                x = 0;
            }
        }
        setInterval(fun,1);
    }
</script>
</html>
图片格式：260*400.
使用循环定时器轻松实现。