一个使用htc来实现的连续滚动公告栏

写了很久了，一直没有优化过。
调用的HTML代码：

<DIV CLASS="ScrollViewDiv" ID="ScrollViewDiv">内容在这里。。。。。。         </DIV>

CSS代码

.ScrollViewDiv {}{
    overflow : hidden;
    height : 55px;
    width : 100%;
    behavior : url(ScrollViewDiv.htc);
}

ScrollViewDiv.htc

<PUBLIC:ATTACH EVENT="onmouseover" ONEVENT="MouseOver()" />
<PUBLIC:ATTACH EVENT="onmouseout" ONEVENT="MouseOut()" />
<PUBLIC:ATTACH EVENT="oncontentready" ONEVENT="Init()" />
<PUBLIC:PROPERTY name="content" id="_innerHtmlID" GET="getContent" PUT="setContent" />
<PUBLIC:PROPERTY NAME="delayTime" ID="_delayTimeID" GET="getDelayTime" PUT="setDelayTime" />
<PUBLIC:PROPERTY NAME="step" ID="_stepID" GET="getStep" PUT="setStep" />
<SCRIPT LANGUAGE="javascript"><!--
var _innerHTML    = "";
var _delayTime    = 300;
var _step        = 1;
var _div1;
var _div2;
var _continueScroll    = true;
function Init()
{
    if (_innerHTML == "")
    {
        _innerHTML    = innerHTML;
    }
    innerHTML    = "";
    _div1        = document.createElement("DIV");
    _div2        = document.createElement("DIV");
    appendChild(_div1);
    appendChild(_div2);
    
    if (_innerHTML == "")
    {
        _div1.innerHTML    = "&nbsp;";
        _div2.innerHTML    = "&nbsp;";
    }
    else
    {
        _div1.innerHTML    = _innerHTML;
        _div2.innerHTML    = _innerHTML;
    }
    
    RollUp();
}
function RollUp()
{
    if (_continueScroll)
    {
        if (_div1.scrollHeight <= offsetHeight)
        {
            //高度小于实际高度时不滚动
            _div2.style.display    = "none";
            scrollTop            = 0;
        }
        else
        {
            _div2.style.display    = "";

            if(_div2.offsetTop - scrollTop <= 0)
            {
                scrollTop -= _div1.offsetHeight;
            }
            else
            {
                scrollTop ++;
            }
        }
    }
    window.setTimeout(RollUp , _delayTime);
}
function getContent()
{
    return _innerHTML;
}
function setContent(value)
{
    _innerHTML    = value;
    
    try
    {
        if (_innerHTML == "")
        {
            _div1.innerHTML    = "&nbsp;";
            _div2.innerHTML    = "&nbsp;";
        }
        else
        {
            _div1.innerHTML    = _innerHTML;
            _div2.innerHTML    = _innerHTML;
        }
    }
    catch (e)
    {
    }
}
function getDelayTime()
{
    return _delayTime;
}
function setDelayTime(value)
{
    try
    {
        _delayTime = parseInt(value , 10);
        if (_delayTime <= 20)
        {
            _delayTime = 20;
        }
    }
    catch (e)
    {
    }
}
function getStep()
{
    return _step;
}
function setStep(value)
{
    _step    = value;
}
function MouseOver()
{
    try
    {
        _continueScroll    = false;
    }
    catch (e)
    {
    }
}
function MouseOut()
{
    try
    {
        _continueScroll    = true;
    }
    catch (e)
    {
    }
}
//--></SCRIPT>