滚动条问题！！！会的来帮帮忙吧

             <div id="demo" style="overflow:hidden; width:300px; height:380px; margin-top:8px; text-align:left;"> 
<div id="demo1" style=" margin-top:12px;"> 
<asp:DataList CellSpacing="3" id="DataList25" runat="server" ItemStyle-BorderStyle="solid" ItemStyle-BorderWidth="1px" ItemStyle-BorderColor="#fefefe" Font-Size="13px" DataSourceID="ObjectDataSource1" Font-Bold="False" OnItemDataBound="DataList25_ItemDataBound" Width="298px" Height="362px"  >
<SeparatorStyle HorizontalAlign="Left" BackColor="Gainsboro" ></SeparatorStyle>
<ItemTemplate>
                             <tr>
<td style="text-align:left; width:130px; padding-left:5px;"><a style="font-size:14px; font-family:宋体; color:Red;" href="SecondHouseInfor/chushouxiangxi.aspx?id=<%# encode(Eval("SHid").ToString())%>&type=<%# Formattitle(Eval("SHFangyuanType").ToString()) %>" title="<%# Eval("SHloupanname") %>"><%# Eval("SHloupanname")%></a></td><td style="text-align:left;"><asp:Label id="NFshiyongmianjiLabel" runat="server" Text='<%# Eval("SHFangyuangaddress") %>' ></asp:Label></td>
<td style="text-align:left; width:70px;"><asp:Label id="NFsumpriceLabel" runat="server" Text='<%# zhuan1(Eval("SHsumprice").ToString()) %>' ></asp:Label><asp:Label
    ID="Label17" runat="server" Text=""></asp:Label></td></tr>
</ItemTemplate>
    <ItemStyle  BorderColor="#FEFEFE" BorderStyle="Solid" BorderWidth="1px" Width="60px" />
</asp:DataList>
 <asp:ObjectDataSource id="ObjectDataSource2" runat="server" TypeName="zlm.BLL.NHouseInforManager" 
 SelectMethod="Getredianfangyuan"></asp:ObjectDataSource>
</div> 
<div id="demo2" style=" margin-top:8px;"></div> 
</div> 
<script language="javascript" type="text/javascript"> 
var speed=30 
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> 
代码就这样   为什么我滚动的数据前后距离大呢  ，就是当从结尾换到头的时候  距离和数据的距离不一样 有点太宽了，谁帮解决下！