private void AlertMessage(string key, string msg)
    {
        string script = "<script>alert(\"" + msg + "\")</script>";
        Page.RegisterClientScriptBlock(key, script);
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        AlertMessage("he", "sdfsf");
    }

TextBox tb = (TextBox)Master.FindControl("m_tbResult");
tb.Text = "ok";

    private byte[] getUnicodeBytesWithBoom(string strMsg)
    {
        byte[] buffer;
        System.Text.UnicodeEncoding enc = new System.Text.UnicodeEncoding();
        buffer = enc.GetBytes(strMsg);

        byte[] boom = new byte[2];
        boom[0] = 0xff;
        boom[1] = 0xfe;

        byte[] ret = new byte[buffer.Length + boom.Length];
        boom.CopyTo(ret, 0);
        buffer.CopyTo(ret, boom.Length);

        return ret;
    }

    private void sendTable(string strTableName)
    {
        string filecontent = TRDatabase.getTableContent(strTableName);

        byte[] buffer = getUnicodeBytesWithBoom(filecontent);

        Response.Clear();
        Response.ContentType = "Application/UnKnown";
        Response.AddHeader("Content-Disposition", "attachment;filename=" + strTableName + ".txt");
        Response.OutputStream.Write(buffer, 0, buffer.Length);
        Response.End();
    }