使用下面的这段向右滚动的js代码，不知道为什么在滚动的中间会有一个空白。

<script type="text/javascript"> var speed = 10; demo2.innerHTML = demo1.innerHTML; demo.scrollLeft = demo.scrollWidth; function Marquee() { if (demo.scrollLeft <= 0) demo.scrollLeft += demo2.offsetWidth; else { demo.scrollLeft--; } } var MyMar = setInterval(Marquee, speed); demo.onmouseover = function () { clearInterval(MyMar) } demo.onmouseout = function () { MyMar = setInterval(Marquee, speed) } </script>求解啊，在线等啊div class="in_ml2" id="demo" style="overflow: hidden;width:980px; height:163px;"> <table align="left" cellpadding="0" cellspace="0" border="0" width="1960"> <tr> <td id="demo1" align="center" style="height: 160px;">然后中间放的是图片<⼀td> <td id="demo2" valign="top"><⼀td> <⼀tr> <⼀table>