JS图片无缝滚动(简单利于使用)

原样复制后，几乎不需要改动就能用了！有问题大家讨论

代码如下:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>滚动代码</title>
<style>
*{ margin:0; padding:0;}
ul,li{ list-style:none;}
.left_1{ width:500px; height:100px; margin:0 auto;}
.left_1 ul{}
.left_1 li{ float:left; width:120px; height:100px; line-height:100px; text-align:center;}
.left_1 p{ width:50px; he
 100px; line-height:100px;}
.left_1_i div{ width:100px; height:100px; line-height:100px; border:1px solid #e5e5e5; margin-left:10px; padding-left:10px;}
</style>
<script language="javascript">
function scrollSZ(con_id,speed,direct){
 var con,items,heightHalf,heightAll;
 var timer;
 speed = parseInt(speed);//获取设置的速度参数
 con = document.getElementById(con_id);
 con.style.overflow = "hidden";
 if(direct == "top"){
  direct = "top";
 }else if(direct == "bottom"){
  direct = "bottom";
 }else{
  direct = "top";
 }

con.innerHTML +=con.innerHTML;
 con.innerHTML +=con.innerHTML;
 items = getChildNodes(con);
 if(items.length < 1){
  return;
 }
 heightAll = 0;
 for(var i=0;i<items.length;i++){
  var numTop,numBottom;
  if (!!window.ActiveXObject){
   numTop = items[i].currentStyle["marginTop"];
   numBottom = items[i].currentStyle["marginBottom"];
  }else{
   numTop = document.defaultView.getComputedStyle(items[i],null)["marginTop"];
   numBottom = document.defaultView.getComputedStyle(items[i],null)["marginBottom"];
  }
  numTop = parseInt(numTop);
  numBottom = parseInt(numBottom);
  numTop += numBottom;
  if(numTop >0){
   heightAll += numTop;
  }
  heightAll += items[i].offsetHeight;
 }
 heightHalf = heightAll/2;
 if(direct == "bottom"){
  con.scrollTop = heightHalf;
  timer = setInterval(_scrollBottom,speed);
 }else if(direct == "top"){
  timer = setInterval(_scrollTop,speed);
 }
 con.onmouseover = function(){
  if(timer){
   clearInterval(timer);
   timer = null;
  }
 };
 con.onmouseout = function(){
  if(!timer){
   if(direct == "top"){
    timer = setInterval(_scrollTop,speed);
   }else if(direct == "bottom"){
    timer = setInterval(_scrollBottom,speed);
   }

}
 };
 function _scrollTop(){
  if(con.scrollTop < heightHalf){
   con.scrollTop += 2;
  }else{
   con.scrollTop = 0;
  }
 }
 function _scrollBottom(){
  if(con.scrollTop > 0){
   con.scrollTop -= 2;
  }else{
   con.scrollTop = heightHalf;
  }
 }
}
function scrollSP(con_id,speed,direct){
 var con,innerCon,timer,items,widthAll,widthHalf;
 speed = parseInt(speed);
 con = document.getElementById(con_id);
 con.style.overflow = "hidden";
 items = getChildNodes(con);
 if(items.length == 1){
  innerCon = items[0];
 }else{
  return;
 }
 innerCon.innerHTML += innerCon.innerHTML;
 innerCon.innerHTML += innerCon.innerHTML;
 items = getChildNodes(innerCon);
 if(items.length<1){
  return;
 }
 widthAll = 0;
 for(var i=0;i<items.length;i++){

}

for(var i=0;i<items.length;i++){
  var numLeft,numRight;
  if (!!window.ActiveXObject){
   items[i].style.styleFloat = "left";
   numLeft = items[i].currentStyle["marginLeft"];
   numRight = items[i].currentStyle["marginRight"];
  }else{
   items[i].style.cssFloat = "left";
   numLeft = document.defaultView.getComputedStyle(items[i],null)["marginLeft"];
   numRight = document.defaultView.getComputedStyle(items[i],null)["marginRight"];
  }
  numLeft = parseInt(numLeft);
  numRight = parseInt(numRight);
  numLeft += numRight;
  if(numLeft>0){
   widthAll += numLeft;
  }
  widthAll += items[i].offsetWidth;
 }
 widthHalf = widthAll/2;
 innerCon.style.width = widthAll+"px";
 if(direct == "left"){
  direct = "left";
 }else if(direct == "right"){
  direct = "right";
 }else{
  direct = "left"
 }
 if(direct == "left"){
  timer = setInterval(_scrollLeft,speed);
 }else if(direct == "right"){
  con.scrollLeft = widthHalf;
  timer = setInterval(_scrollRight,speed);
 }
 con.onmouseover = function(){
  if(timer){
   clearInterval(timer);
   timer = null;
  }
 }
 con.onmouseout = function(){
  if(direct == "left"){
   timer = setInterval(_scrollLeft,speed);
  }else{
   timer = setInterval(_scrollRight,speed);
  }
 }
 function _scrollLeft(){

if(con.scrollLeft<widthHalf){
   con.scrollLeft += 2;
  }else{
   con.scrollLeft = 0;
  }
 }
 function _scrollRight(){
  if(con.scrollLeft>0){
   con.scrollLeft -= 2;
  }else{
   con.scrollLeft = widthHalf;
  }
 }
}
function getChildNodes(obj){//获取元素子节点
 var childList,list;
 childList = new Array();
 list = obj.childNodes;
 for(var i=0;i<list.length;i++){
  if(list[i].nodeType == 1)
  childList[childList.length] = list[i];
 }
 return childList;
}
</script>
</head>
<body>

<div id="left_1" class="left_1">
 <div class="left_1_i">
  <p>1</p>
     <p>2</p>
     <p>3</p>
     <p>4</p>
     <div>b</div>
     <div>a</div>
 </div>
</div>
<script language="javascript">scrollSP("left_1",10,"right");</script>
</body>
</html>