function pagebar(td,img)
{
	if (td.style.display=="") 
	{	img.src="images/an_help.gif";
		img.alt="帮助";
		td.style.display="none";
	}
	else
	{	img.src="images/an_helpno.gif";
		img.alt="关闭帮助";
		td.style.display="";
	}
}