protected override void CreateChildControls()
        {
            this.Controls.Clear();

            btnClose = new Button();
            btnClose.ID = "btnClose";
            btnClose.Text = "  关闭  ";

            this.Controls.Add(btnClose);
        }

<input type="submit" id="Option1_btnClose" value="  关闭  " name="Option1$btnClose">

  HtmlInputButton htb = new HtmlInputButton();
        htb.Attributes.Add("type", "button");