Marquee不留白！

<div style="width: 201px; height: 149px; overflow: hidden" id="demo">
                                                        <div id="demo1">
                                                            <img src="Image/tu1.jpg" width="201" height="149"><br>
                                                            <img src="Image/tu2.jpg" width="201" height="149"><br>
                                                            <img src="Image/tu3.jpg" width="201" height="149">
                                                        </div>
                                                        <div id="demo2">
                                                        </div>
                                                    </div>

                                                    <script>
                                                        var speed = 60;
                                                        demo2.innerHTML = demo1.innerHTML
                                                        function Marquee() {
                                                            if (demo2.offsetTop - demo.scrollTop <= 0)
                                                                demo.scrollTop -= demo1.offsetHeight;
                                                            else
                                                                demo.scrollTop++;
                                                        }
                                                        var MyMar = setInterval(Marquee, speed)
                                                        demo.onmouseover = function() { clearInterval(MyMar) }
                                                        demo.onmouseout = function() { MyMar = setInterval(Marquee, speed) }
</script>