public Form27()
        {
            InitializeComponent();
            this.webBrowser1.Navigate("http://localhost:9584/");
            this.webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
        }

        void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            //throw new NotImplementedException();

            System.Windows.Forms.HtmlDocument HTMLDocument = this.webBrowser1.Document;
            System.Windows.Forms.HtmlElement closeBtn = HTMLDocument.GetElementById("ctl00$MainContent$btnClick"); //html中元素标签
            closeBtn.MouseDown += new HtmlElementEventHandler(closeWindw);// // HTML点击按钮
        }

        void closeWindw(object o, EventArgs  e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

------解决方案--------------------
http://blog.csdn.net/zzzzzzzert/article/details/7787481