<!DOCTYPE HTML>
<html lang="en-US">
<head>
  <meta charset="UTF-8">
  <title>無(wú)縫滾動(dòng)——上下</title>
  <style type="text/css">
  *{margin:0;padding:0;}
  li{list-style:none;}
  img{border:0;}
  #scroll{width:178px;margin:50px auto;position:relative;}
  .btn{display:block;width:27px;height:27px;margin-left:auto;margin-right:auto;cursor:pointer;}
  .up{background:url(images/up.gif);}
  .down{background:url(images/down.gif);}
  .content{margin:10px 0;height:440px;overflow:hidden;position:relative;}
  .content ul{position:absolute;top:0;left:0;}
  .content li{height:110px;}
  </style>
</head>
<body>
  <div id="scroll">
    <a href="javascript:;" id="up" class="btn up"></a>
    <div class="content">
      <ul>
        <li><a href="#" title="111"><img src="images/1.jpg" alt="111" width="178" height="108"/></a></li>
        <li><a href="#" title="222"><img src="images/2.jpg" alt="222" width="178" height="108"/></a></li>
        <li><a href="#" title="333"><img src="images/3.jpg" alt="333" width="178" height="108"/></a></li>
        <li><a href="#" title="444"><img src="images/4.jpg" alt="444" width="178" height="108"/></a></li>
      </ul>
    </div>
    <a class="btn down" href="javascript:;" id="down"></a>
  </div>
</body>
</html>
<script type="text/javascript">
window.onload = function(){
  var oDiv = document.getElementById('scroll');
  var btnUp = document.getElementById('up');
  var btnDown = document.getElementById('down');
  var oUl = oDiv.getElementsByTagName('ul')[0];
  var timer = null;
  var speed = -1;
  oUl.innerHTML += oUl.innerHTML;
  setTimeout(move,1500);
  btnUp.onclick = function(){
    clearInterval(timer);
    speed = -1;
    move();
  };
  btnDown.onclick = function(){
    clearInterval(timer);
    speed = 1;
    move();
  };
  oUl.onmouseover = function(){
    clearInterval(timer);
  };
  oUl.onmouseout = function(){
    move();
  };
  function move(){
    timer = setInterval(function(){
      oUl.style.top = oUl.offsetTop + speed + 'px';
      if(oUl.offsetTop <= - oUl.offsetHeight / 2){
        oUl.style.top = '0';
      }else if(oUl.offsetTop >= 0){
        oUl.style.top = - oUl.offsetHeight / 2 + 'px';
      };
    },30);
  };
};
</script>

如果要改變移動(dòng)速度，修改 speed 的值即可，初始默認(rèn)為向上移動(dòng)，即速度為負(fù)數(shù)。

更多關(guān)于JavaScript相關(guān)內(nèi)容感興趣的讀者可查看本站專題：《JavaScript切換特效與技巧總結(jié)》、《JavaScript查找算法技巧總結(jié)》、《JavaScript動(dòng)畫(huà)特效與技巧匯總》、《JavaScript錯(cuò)誤與調(diào)試技巧總結(jié)》、《JavaScript數(shù)據(jù)結(jié)構(gòu)與算法技巧總結(jié)》、《JavaScript遍歷算法與技巧總結(jié)》及《JavaScript數(shù)學(xué)運(yùn)算用法總結(jié)》

希望本文所述對(duì)大家JavaScript程序設(shè)計(jì)有所幫助。

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