这个js走马灯为什么不循环滚动

C# code

<div id="demoabc" style="overflow:hidden;width:710px;  white-space:nowrap;">        <div id="demoabc1">        <%=gonggaoinfo%>        </div>        <div id="demoabc2"></div>    </div>             <script type="text/javascript">        var dirabc = 1//每步移动像素，数大为快        var speedabc = 20//循环周期（毫秒）数大为慢        demoabc2.innerHTML = demoabc1.innerHTML        function Marqueeabc() {//正常移动            //offsetWidth元素宽            //scrollLeft页面利用滚动条滚动到右侧时，隐藏在滚动条左侧的页面的宽度            if (dirabc > 0 && (demoabc2.offsetWidth - demoabc.scrollLeft) <= 0) demoabc.scrollLeft = 0            if (dirabc < 0 && (demoabc.scrollLeft <= 0)) demoabc.scrollLeft = demoabc2.offsetWidth            demoabc.scrollLeft += dirabc                       demoabc.onmouseover = function () { clearInterval(MyMarabc) } //暂停移动            demoabc.onmouseout = function () { MyMarabc = setInterval(Marqueeabc, speedabc) } //继续移动                   }        function r_leftabc() { if (dirabc = -1) dirabc = 1 } //换向左移        function r_rightabc() { if (dirabc = 1) dirabc = -1 } //换向右移        var MyMarabc = setInterval(Marqueeabc, speedabc)       </script>                  </div>

[解决办法]
有滚动啊.可能是你的<%=gonggaoinfo%>内容太短.
或者你将width:710px改成width:50px可以看出有滚动.
[解决办法]
参考：
http://www.cnblogs.com/insus/archive/2012/03/11/2389855.html