//参数：目标标签ID，显示高度，暂停时间(毫秒),速度
var scrollTimer;
function scrollText(oId,sleep,step,vlen)
{
	//alert(oId);
	var obj = $(oId);
	if(obj==null)
		return;
	var scrollHeight = obj.scrollHeight - obj.offsetHeight;
	if(scrollHeight == 0)
	{
		return;
	}
		

	if(step==null)
		step = 100;
	if(sleep==null)
		sleep = 5000;
	if(vlen==null)
	 {
	     vlen = obj.offsetHeight;
	     obj.scrollTop = 0;
	     scrollTimer = setTimeout("scrollText('" + oId + "'," + sleep + "," + step + "," + vlen + ")",sleep);
	     return;
	 }
     var tlen = 0
	 if(vlen<10)
		tlen = vlen;
	 else
	 	tlen = parseInt(vlen * 0.2);
		
	vlen -= tlen;
	
	var time = step;
	obj.scrollTop += tlen;
	//document.title = vlen + "," + obj.scrollTop + "," + scrollHeight;
	if(vlen==0)
	{
		vlen = obj.offsetHeight;
		scrollTimer = setTimeout("scrollText('" + oId + "'," + sleep + "," + step + "," + vlen + ")",sleep);
	    return;
	}
	if(obj.scrollTop >= scrollHeight)	
		obj.scrollTop = 0;

	scrollTimer = setTimeout("scrollText('" + oId + "'," + sleep + "," + step + "," + vlen + ")",time);
}