function $(obj)
{
return document.getElementById(obj);
}
function $page(url,page)
{
    var val = $("#pn").value;

    if(val == "")
    {
       alert("请输入数字");
        return false;
    }
    else
    {
        if(val > page)
        {
            url += "-" + page;
        }
        else if(val < 1)
        {
            url += "-1";
        }
        else
        {
            url += "-" + val;
        }
        
    }
    location.href = url + "/index.shtml";
}