function admin_login_chk()
{
  var username=document.admin_frm.username.value;
  var password=document.admin_frm.password.value;
  if (username=="" || username==null)
  {
    alert("对不起！\n\n请先输入登陆用户名！");
    document.admin_frm.username.focus();
    return;
  }
  if (password=="" || password==null)
  {
    alert("对不起！\n\n请先输入登陆密码！");
    document.admin_frm.password.focus();
    return;
  }
  document.admin_frm.submit();
}

document.admin_frm.password.focus();