拖曳那点事(拖曳时到浏览器底部时自动向下流动)

这样???
<html>
    <head>
        <meta http-equiv="content-type" content="text/html; charset=gb2312" />
        <meta http-equiv="content-language" content="zh-CN" />
        <meta http-equiv="MSThemeCompatible" content="Yes" />
        <meta http-equiv="imagetoolbar" content="no" />
        <title>TEST</title>
        <style type="text/css"><!--
        a, a:link{text-decoration: none; color:#000000; font-size:9pt;}
        a:visited{text-decoration: none; color:#000000;}
        a:hover{text-decoration: underline; color:red;}
        body, td, p, li, div, select{font-size:9pt; font-family:"宋体";}
        --></style>
<script type="text/JavaScript">
var DR={};
var MaxHeight,WinHeight;
window.onload=function(){MaxHeight=document.body.scrollHeight;WinHeight=document.body.offsetHeight;}
document.onmousedown=function(e)
{
    e =    e||event;
    var tag=e.srcElement?e.srcElement:e.target;
    if(tag.id != 'T1') return;
    var o=document.getElementById("T1");
    var c=document.getElementById("T2");
    DR.c=c;
    DR.o= o;
    DR.x= e.clientX - o.offsetLeft;
    DR.y= e.clientY - o.offsetTop;
    DR.w= o.offsetWidth;
    DR.h= o.offsetHeight;
    DR.c.style.width=DR.w+"px";
    DR.c.style.height=DR.h+"px";
    if(DR.c.setCapture)DR.c.setCapture();
}
document.onmousemove=function(e)
{
    e=e||event;
    if(DR.o!=null)
    {           
        var toY=(e.clientY-DR.y);
        if(!DR.SI)
        {          
          if((WinHeight+document.body.scrollTop<MaxHeight)&&(toY+DR.w>=WinHeight||document.body.scrollTop>0))
            DR.SI=setInterval("scrollWin()",100);
          else
          { 
            var toX=(e.clientX-DR.x);
            DR.c.style.display='block';          
            DR.c.style.top= toY+"px";   
            DR.c.style.left= toX+"px"; 
          } 
        }
        else//在滚动
        {
           DR.c.style.left=e.clientX-DR.x+"px";
           DR.c.style.top=(e.clientY-DR.y)+document.body.scrollTop+"px";
        }          
    }
}
function scrollWin()
{
  if(DR.c)
  {
    var top=parseFloat(DR.c.style.top)+10;
    if(top+DR.h<=MaxHeight)
    {  
      DR.c.style.top=top+"px";
      window.scrollBy(0,10);
    }
    else if(DR.SI)
      clearInterval(DR.SI);
  }
}
document.onmouseup=function()
{
    if(DR.o!=null)
    {        DR.c.style.display='none';
        DR.o.style.left= DR.c.style.left;
        DR.o.style.top= DR.c.style.top;
        if(DR.SI)
        {  
           clearInterval(DR.SI);
           DR.SI=null;
        }
        if(DR.c.releaseCapture)DR.c.releaseCapture();
        DR={};
    }
}</script>
    </head>
    <body onselectstart="return false;">
        <div>PAGE START</div>
        <p style="color:#FF0000;">目地:一次性拖动DIV到浏览器底部PAGE END处<br></p>
        <p style="color:#339900;">在DIV上按下鼠标拖曳层到浏览器底部时浏览器滚动条自动向下走,当然这时鼠标上的层也要跟着向下走<br></p>
        <div id="T1" style="position:absolute;zIndex:100;left:300px;top:200px;width:100px;height:100px;background:#FFFF99;border:1px red solid;cursor:move;"> TEST 1</div>
        <div id="T2" style="display:none;position:absolute;zIndex:101;background:#99FFCC;border:1px #339900 solid;cursor:move;filter:alpha(opacity=60);"></div>
        <div style="height:1200px;"></div>
        <div style="margin:50px;">PAGE END</div>
    </body>
</html>