function JumpPagedown(filename,pagecount)
{
	var url;
	if (document.getElementById("downpage").value <= pagecount && document.getElementById("downpage").value > 0 && document.getElementById("downpage").value !="")
	{
		if(document.getElementById("downpage").value>1)
		{
			url = filename + "_"+(document.getElementById("downpage").value-1)+".html";
		}
		else
		{
			url = filename +".html";
		}
		location.href = url; 
	}
    else
	{	
		url = "javascript:;";
		location.href = url; 
	}
}