利用Scrip实现走马灯效果[无缝连接、循环滚动]

下面说一下这个相对简单的实现思路：
一个设定宽度并且隐藏超出它宽度的内容的容器demo，里面放demo1和demo2，demo1是滚动内容,demo2为demo1的直接克隆，通过不断改变demo1的scrollTop或者scrollLeft达到滚动的目的，当滚动至demo1与demo2的交界处时直接跳回初始位置，因为demo1与demo2一样，所以分不出跳动的瞬间，从而达到“无缝”滚动的目的。 
先了解一下对象的几个的属性：

innerHTML:设置或获取位于对象起始和结束标签内的 HTML
scrollHeight: 获取对象的滚动高度。 
scrollLeft:设置或获取位于对象左边界和窗口中目前可见内容的最左端之间的距离
scrollTop:设置或获取位于对象最顶端和窗口中可见内容的最顶端之间的距离
scrollWidth:获取对象的滚动宽度
offsetHeight:获取对象相对于版面或由父坐标 offsetParent 属性指定的父坐标的高度
offsetLeft:获取对象相对于版面或由 offsetParent 属性指定的父坐标的计算左侧位置
offsetTop:获取对象相对于版面或由 offsetTop 属性指定的父坐标的计算顶端位置 
offsetWidth:获取对象相对于版面或由父坐标 offsetParent 属性指定的父坐标的宽度 

一、向上的无缝循环滚动

<!--  指向链接图片的URL  -->
< base href = " http://www.it365cn.com " >
< div align = " center "  id = " demo "  style = " overflow:hidden;height:200px;width:95px;border-width:1px 1px 1px 1px;border-style:dotted dotted dotted dotted; " >
     < div id = " demo1 " >
         <!--  定义内容 -->
         < img src = " images/logo_1.gif " >
         < img src = " images/logo/flashempire.gif " >
         < img src = " images/logo.gif " >
         < img src = " images/logo/5dmedia.gif " >
         < img src = " images/logo/macromedia.gif " >
         < img src = " images/logo/sucaiw.gif " >
         < img src = " images/logo/blueieda.gif " >
         < img src = " images/logo/htmlcn.gif " >
         < img src = " images/logo/fwcn.gif " >
     </ div >
     < div id = " demo2 " ></ div >
</ div >

< script language = " javascript "  type = " text/javascript " >
<!--
var  demo  =  document.getElementById( " demo " );
var  demo1  =  document.getElementById( " demo1 " );
var  demo2  =  document.getElementById( " demo2 " );
var  speed = 10 ;     // 滚动速度值，值越大速度越慢
demo2.innerHTML  =  demo1.innerHTML     // 克隆demo2为demo1
function  Marquee() ... {
    if(demo2.offsetTop-demo.scrollTop<=0)    //当滚动至demo1与demo2交界时
        demo.scrollTop-=demo1.offsetHeight    //demo跳到最顶端
    else...{
        demo.scrollTop++
    }
}
var  MyMar  =  setInterval(Marquee,speed);         // 设置定时器
demo.onmouseover  =   function () ... {clearInterval(MyMar)}      // 鼠标经过时清除定时器达到滚动停止的目的
demo.onmouseout  =   function () ... {MyMar = setInterval(Marquee,speed)}      // 鼠标移开时重设定时器
-->
</ script >

二、向下的无缝循环滚动

<!--  指向链接图片的URL  -->
< base href = " http://www.it365cn.com " >
< div align = " center "  id = " demo "  style = " overflow:hidden;height:200px;width:95px;border-width:1px 1px 1px 1px;border-style:dotted dotted dotted dotted; " >
     < div id = " demo1 " >
         <!--  定义内容 -->
         < img src = " images/logo_1.gif " >
         < img src = " images/logo/flashempire.gif " >
         < img src = " images/logo.gif " >
         < img src = " images/logo/5dmedia.gif " >
         < img src = " images/logo/macromedia.gif " >
         < img src = " images/logo/sucaiw.gif " >
         < img src = " images/logo/blueieda.gif " >
         < img src = " images/logo/htmlcn.gif " >
         < img src = " images/logo/fwcn.gif " >
     </ div >
     < div id = " demo2 " ></ div >
</ div >

< script language = " javascript "  type = " text/javascript " >
<!--
var  demo  =  document.getElementById( " demo " );
var  demo1  =  document.getElementById( " demo1 " );
var  demo2  =  document.getElementById( " demo2 " );
var  speed = 10 ;     // 数值越大滚动速度越慢
demo2.innerHTML  =  demo1.innerHTML;
demo.scrollTop  =  demo.scrollHeight;
function  Marquee() ... {
    if(demo1.offsetTop-demo.scrollTop>=0)
        demo.scrollTop+=demo2.offsetHeight
    else...{
        demo.scrollTop--
    }
}
var  MyMar  =  setInterval(Marquee,speed);
demo.onmouseover  =   function () ... {clearInterval(MyMar)}
demo.onmouseout  =   function () ... {MyMar = setInterval(Marquee,speed)}
-->
</ script >

三、向左的无缝循环滚动

<!--  指向链接图片的URL  -->
< base href = " http://www.it365cn.com " >
< div align = " center "  id = " demo "  style = " overflow:hidden;height:33px;width:500px;border-width:1px 1px 1px 1px;border-style:dotted dotted dotted dotted; " >
   < table border = " 0 "  cellspacing = " 0 "  cellpadding = " 0 " >
     < tr >
       < td id = " demo1 " >< img src = " images/logo_1.gif " >< img src = " images/logo/flashempire.gif " >< img src = " images/logo.gif " >< img src = " images/logo/5dmedia.gif " >< img src = " images/logo/macromedia.gif " >< img src = " images/logo/sucaiw.gif " >< img src = " images/logo/blueieda.gif " >< img src = " images/logo/htmlcn.gif "  border = " 0 " ></ td >
       < td id = " demo2 " >& nbsp; </ td >
     </ tr >
   </ table >
</ div >

< script language = " javascript "  type = " text/javascript " >
<!--
var  demo  =  document.getElementById( " demo " );
var  demo1  =  document.getElementById( " demo1 " );
var  demo2  =  document.getElementById( " demo2 " );
var  speed = 10 ;     // 数值越大滚动速度越慢
demo2.innerHTML  =  demo1.innerHTML
function  Marquee() ... {
    if(demo2.offsetWidth-demo.scrollLeft<=0)
        demo.scrollLeft-=demo1.offsetWidth
    else...{
        demo.scrollLeft++
    }
}
var  MyMar  =  setInterval(Marquee,speed);
demo.onmouseover  =   function () ... {clearInterval(MyMar)}
demo.onmouseout  =   function () ... {MyMar = setInterval(Marquee,speed)}
-->
</ script >

四、向右的无缝循环滚动

<!--  指向链接图片的URL  -->
< base href = " http://www.it365cn.com " >
< div align = " center "  id = " demo "  style = " overflow:hidden;height:33px;width:500px;border-width:1px 1px 1px 1px;border-style:dotted dotted dotted dotted; " >
   < table border = " 0 "  cellspacing = " 0 "  cellpadding = " 0 " >
     < tr >
       < td id = " demo1 " >< img src = " images/logo_1.gif " >< img src = " images/logo/flashempire.gif " >< img src = " images/logo.gif " >< img src = " images/logo/5dmedia.gif " >< img src = " images/logo/macromedia.gif " >< img src = " images/logo/sucaiw.gif " >< img src = " images/logo/blueieda.gif " >< img src = " images/logo/htmlcn.gif "  border = " 0 " ></ td >
       < td id = " demo2 " >& nbsp; </ td >
     </ tr >
   </ table >
</ div >

< script language = " javascript "  type = " text/javascript " >
<!--
var  demo  =  document.getElementById( " demo " );
var  demo1  =  document.getElementById( " demo1 " );
var  demo2  =  document.getElementById( " demo2 " );
var  speed = 10 ;     // 数值越大滚动速度越慢
demo2.innerHTML  =  demo1.innerHTML;
demo.scrollLeft  =  demo.scrollWidth;
function  Marquee() ... {
    if(demo.scrollLeft<=0)
        demo.scrollLeft+=demo2.offsetWidth
    else...{
        demo.scrollLeft--
    }
}
var  MyMar  =  setInterval(Marquee,speed)
demo.onmouseover  =   function () ... {clearInterval(MyMar)}
demo.onmouseout  =   function () ... {MyMar = setInterval(Marquee,speed)}
-->
</ script >