JavaScript 实现无缝滚动效果详解

完整代码实现

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>无缝滚动2</title>
 <style type="text/css"> 
 *{
  padding: 0;
  margin:0;
 }
 #div1{
  position: relative;
  width: 800px;
  height: 200px;
  background:red;
  margin:100px auto;
  overflow: hidden;
 }
 #div1 ul{
  position: absolute;
  left: 0;
  top: 0;

 }
 #div1 ul li{
  float: left;
  list-style: none;
  width: 200px;
  height: 200px;
 }
 </style>
 <script type="text/javascript">
 window.onload=function()
 {
  var oDiv = document.getElementById('div1');
  var oUl = oDiv.getElementsByTagName('ul')[0];
  var aLi = oDiv.getElementsByTagName('li');
  var aA = document.getElementsByTagName('a');
  var speed = 3;
  oUl.innerHTML=oUl.innerHTML+oUl.innerHTML;
  oUl.style.width=aLi.length*aLi[0].offsetWidth+'px';

  var timer=setInterval(move,30);

  function move()
  { 
   if (oUl.offsetLeft<=-oUl.offsetWidth/2) {
    oUl.style.left="0";
    } 
    if(oUl.offsetLeft>0){
     oUl.style.left=-oUl.offsetWidth/2+'px';
    }
    oUl.style.left=oUl.offsetLeft+speed+'px';
  };
  oDiv.onmouseover=function()
  {
   clearInterval(timer);
  };
  oDiv.onmouseout=function()
  {
   timer=setInterval(move,30);
  };
  aA[0].onclick=function()
  {
   speed=-3;
  };
  aA[1].onclick=function()
  {
   speed=3;
  };
 };
 </script>
</head>
<body>
 <a href="javascript:;">向左</a>
 <a href="javascript:;">向右</a>
 <div id="div1">
  <ul>
   <li><img src="images/n1.jpg"></li>
   <li><img src="images/n2.jpg"></li>
   <li><img src="images/n3.jpg"></li>
   <li><img src="images/n4.jpg"></li>
  </ul>
 </div>
</body>
</html>