div内容滚动的高级应用问题

Question

给你个例子 自己研究下
 var speed=1;
 var link_logo = document.getElementById("link_logo");
 var link_logo1 = document.getElementById("link_logo1");
 var link_logo2 = document.getElementById("link_logo2");
 link_logo2.innerHTML=link_logo1.innerHTML;
 function Marquee2()
 {
    if(link_logo2.offsetTop-link_logo.scrollTop<=0)
    link_logo.scrollTop-=link_logo1.offsetHeight
    else
    {
        link_logo.scrollTop=link_logo.scrollTop+4;
        if((parseInt(link_logo.scrollTop)%parseInt('112'))==parseInt('0'))
            overTime();     
}
 }
 var MyMar2=setInterval(Marquee2,speed);
 function startTime()
 {
    MyMar2=setInterval(Marquee2,speed); 
 }
 function overTime()
 {
    clearInterval(MyMar2);
    setTimeout(startTime,2000);
 }
<div class="gd" id="link_logo" style="overflow: hidden; width: 238px; height: 110px">
                            <div id="link_logo1">
                                <asp:Repeater ID="RpAping" runat="server">
                                    <ItemTemplate>
                                        <dl>
                                            <dt><a href="<%=MyTheme.ServerUrl %>/Shop/showcoment.aspx?Id=<%# Eval("ShAp_ShopId") %>">
                                                <img src="<%# (!String.IsNullOrEmpty(Eval("ShIn_Photo").ToString()))?Eval("ShIn_Photo"):MyTheme.ServerUrl+"/uploads/photo/120img.gif"%>"
                                                    border="0" /></a> </dt>
                                            <dd>
                                                <span><a href="<%=MyTheme.ServerUrl %>/Shop/showcoment.aspx?Id=<%# Eval("ShAp_ShopId") %>"
                                                    target="_blank">
                                                    <%# Eval("ShIn_Name") %>
                                                </a></span>
                                                <br />
                                                <%# MyConvert.Get_Str(Eval("ShAp_Feeling","{0}"),140) %>
                                            </dd>
                                        </dl>
                                    </ItemTemplate>
                                </asp:Repeater>
                            </div>
                            <div id="link_logo2">
                            </div>
                        </div>