function  checkform(postform)
{
    var username = document.getElementById("userName");
    if(username.value=="")
    {
        changeSH("uw");
        return false;
    }
    else
    {
       if(isUsername(username.value)>0)
       {
          changeSH("uw");
          return false;
       }
    }
    var password = document.getElementById("password");
    if(password.value=="")
    {
        changeSH("pw");
        return false;
    }
    document.getElementById("login_submit").value="login";
}

function changeSH(obj)
{
    document.getElementById(obj).style.display="block";
}

//防止被加入Iframe中
if (self != top) top.location = self.location;