<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title>无缝滚动——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;position:absolute;left:75px;}
.up{background:url(images/up.gif);top:0;}
.down{background:url(images/down.gif);top:490px;}
.content{height:440px;overflow:hidden;position:relative;top:40px;}
.content ul{position:absolute;top:0;left:0;}
.content li{height:110px;}
</style>
</head>
<body>
<div id="scroll">
<a href="javascript:;" class="btn up"></a>
<a href="javascript:;" class="btn down"></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>
</div>
</body>
</html>
<script type="text/javascript" src="scroll.js"></script>
<script type="text/javascript">
window.onload = function(){
scroll('top',1,1000);
};
</script>
scroll.js：
/**********
功能：实现水平或垂直无缝滚动
参数：direction方向，总共4个值：left,right,top,bottom
speed移动距离
iTime多少时间后开始移动，若不写则页面加载完开始移动
**********/
function scroll(direction,speed,iTime){
var oDiv = document.getElementById('scroll');
var oUl = oDiv.getElementsByTagName('ul')[0];
var aLi = oDiv.getElementsByTagName('li');
var aBtn = oDiv.getElementsByTagName('a');
var timer = null;
var iSpeed = 0;
var flag = true; //判断水平移动还是垂直移动
oUl.innerHTML += oUl.innerHTML;
switch(direction){
case 'left':
iSpeed = -speed;
oUl.style.width = aLi[0].offsetWidth * aLi.length + 'px';
flag = true;
break;
case 'right':
iSpeed = speed;
oUl.style.width = aLi[0].offsetWidth * aLi.length + 'px';
flag = true;
break;
case 'top':
iSpeed = -speed;
flag = false;
break;
case 'bottom':
iSpeed = speed;
flag = false;
break;
};
setTimeout(move,iTime);
//左按钮和上按钮
aBtn[0].onclick = function(){
clearInterval(timer);
iSpeed = -speed;
move();
};
//右按钮和下按钮
aBtn[1].onclick = function(){
clearInterval(timer);
iSpeed = speed;
move();
};
oUl.onmouseover = function(){
clearInterval(timer);
};
oUl.onmouseout = function(){
move();
};
function move(){
timer = setInterval(function(){
if(flag){
oUl.style.left = oUl.offsetLeft + iSpeed + 'px';
if(oUl.offsetLeft < -oUl.offsetWidth / 2){
oUl.style.left = '0';
}else if(oUl.offsetLeft > 0){
oUl.style.left = - oUl.offsetWidth / 2 + 'px';
}
}else{
oUl.style.top = oUl.offsetTop + iSpeed + 'px';
if(oUl.offsetTop <= - oUl.offsetHeight / 2){
oUl.style.top = '0';
}else if(oUl.offsetTop >= 0){
oUl.style.top = - oUl.offsetHeight / 2 + 'px';
};
};
},30);
};
};
需要注意的是：html 结构必须要像上面的结构一样。