请问一个脚本有关问题

public class MsgBoxShow{    public MsgBoxShow()    {        //        //TODO: 在此处添加构造函数逻辑        //    }    /// <summary>    /// 显示“确定”，点击后转到预设的网址    /// </summary>    /// <param name="strMsg">提示信息</param>    /// <param name="URL">转跳网址</param>    public static void MsgBoxShowInfoAndRedirct(System.Web.UI.Page page, string strMsg, string URL)    {        StringBuilder builder = new StringBuilder();        builder.Append("<language='javascript' defer>");        builder.AppendFormat("alert('{0}');",strMsg);        builder.AppendFormat("top.location.href='{0}';", URL);        builder.Append("</script>");        page.RegisterStartupScript("message", builder.ToString());    }}

protected void btnSubmit_Click(object sender, EventArgs e)    {        SqlConnection conn = new SqlConnection();        conn.ConnectionString = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;        SqlCommand cmd = new SqlCommand();        cmd.Connection = conn;        cmd.CommandText = "select * from users where username='" + txtUserName.Text.Trim() + "'";        conn.Open();        SqlDataReader dr = cmd.ExecuteReader();        if (dr.Read())        {            if (dr[2].ToString() == txtPwd.Text.Trim())            {                MsgBoxShow.MsgBoxShowInfoAndRedirct(this,"登陆成功！", "ManageNews.aspx");                //Session["UserName"] = txtUserName.Text.Trim();                //Response.Redirect("NewsManage.aspx");            }            else            {                MsgBoxShow.MsgBoxShowInfoAndRedirct(this, "密码错误！请重新输入", "login.aspx");            }        }        else        {            MsgBoxShow.MsgBoxShowInfoAndRedirct(this, "查无此用户！请重新输入", "login.aspx");        }    }