无缝滚动

<!DOCTYPE html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title></title>
    <style>
        *{
            margin:0px;
            padding:0px;
            
        }
        
       #main {
           height:200px;
       }
        #div1{
            width:1200px;
            height:200px;
            background-color:salmon;
            position:relative;

            background-color:red;
            overflow:hidden;
            float:left;
            
        }
        #div1 ul{
            position:absolute;
            left:0px;
            top:0px;

        }
        #div1 ul li{
            float:left;
            list-style:none;
            width:300px;
            height:200px;
        }
        #goLeft{
            float:left;
        }
        #goLeft{
            float:left;
        }
    </style>
    <script>
        window.onload = function () {
            var oDiv1 = document.getElementById("div1");
            var oUl = oDiv1.getElementsByTagName("ul")[0];
            var aLi = oUl.getElementsByTagName("li");
            var speed = -2;
            var timer;


            oUl.innerHTML = oUl.innerHTML + oUl.innerHTML;
            oUl.style.width = aLi[0].offsetWidth * aLi.length + "px";
            function move() {
               
                if (oUl.offsetLeft < -oUl.offsetWidth / 2) {
                    oUl.style.left = "0" + px;
                    
                    
                }

                if (oUl.offsetLeft > 0) {
                    oUl.style.left = -oUl.offsetWidth / 2 + "px";
                }

                oUl.style.left = oUl.offsetLeft + speed + "px";
               
            }

            timer = setInterval(move, 30);
           
            var oGoRight = document.getElementById("goRight");
            var oGoLeft = document.getElementById("goLeft");
           oGoLeft.onclick = function () {
                speed = -2;
            }
            oGoRight.onclick = function () {
                speed = 2;
            }
            
            oDiv1.onmouseover = function () {

                clearInterval(timer);
            }
            oDiv1.onmouseout = function () {
                timer = setInterval(move, 30);
            }
        }
    </script>
</head>
<body>
    <div id="main">
        <img id="goLeft" src="D:html滚动的图片picleft.png" />
        <div id="div1">
            <ul>
                <li><img src="D:html滚动的图片picaaa.jpg" /></li>
                <li><img src="D:html滚动的图片picbb.jpg" /></li>
                <li><img src="D:html滚动的图片picccc.jpg" /></li>
                <li><img src="D:html滚动的图片picddd.jpg" /></li>
            </ul>
        </div>
        <img id="goRight" src="D:html滚动的图片pic
ight.png" />
    </div>
</body>
</html>