ASP加JS做的滚动条运行一断时间就停止了是什么问题啊

<div id="demo" style="OVERFLOW: hidden; WIDTH:200px; HEIGHT:400px; padding-top:0px;margin-left:45px;margin-bottom:0px;text-align: left;vertical-align:bottom">
                <div id="demo1" style="margin:0px;">
                <%
                set rs=server.CreateObject("adodb.recordset")
                sql="select * from Buyinfo order by adddate desc"
                rs.open sql,conn,1,1
                if rs.recordcount=0 then
                   response.Write("<tr><td colspan=3>暂时无定单……</td></tr>")
                   else
                   for i=0 to rs.pagesize
                if rs("sex")="1" then
                sex="先生"
                else
                sex="女士"
                end if
            %>
            <%
                address=left(rs("addr"),2)
                user=left(rs("user"),1)
            %>   
            <div style="margin-top:5px;"><span style="color:#FFFFFF; font-size:12px;"><%=address%><%=user%><%=sex%><%=rs("count")%>盒</span></div>
            <%
                rs.movenext
                if rs.eof then
                exit for
                end if
                next
                end if
            %>
                </div>
                <div id="demo2"></div>
            </div>
            <SCRIPT>
                    var rollspeed=50
                    demo2.innerHTML=demo1.innerHTML
                    function Marquee(){
                        if(demo2.offsetTop-demo.scrollTop<=0)
                        demo.scrollTop-=demo1.offsetHeight
                        else{
                        demo.scrollTop++
                        }
                    }

                    var MyMar=setInterval(Marquee,rollspeed)
                    demo.onmouseover=function() {clearInterval(MyMar)}
                    demo.onmouseout=function() {MyMar=setInterval(Marquee,rollspeed)}
                </SCRIPT>