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 list1 = HTMLDocument.GetElementById("ctl00$MainContent$btnClick");
            list1.MouseDown += new HtmlElementEventHandler(closeWindw);// // 指定监视
        }

        void closeWindw(object o, EventArgs  e)
        {
            this.Close();
        }

------解决方案--------------------
探讨




------解决方案--------------------

<script type="text/javascript">
   btnClose.onmousedown = function() {
       window.external.close();
   }
</script>


namespace CLose
{
   [System.Runtime.InteropServices.ComVisibleAttribute(true)]
   public partial class Form1 : Form
   {
       public Form1()
       {
           InitializeComponent();
           webBrowser1.ObjectForScripting = this;//允许脚本调用
           webBrowser1.Url = new Uri(@"E:\project\WebBrowse\CLose\close.htm");
       }
       private void close()
       {
           this.close();
       }
   }
}


------解决方案--------------------

js中调用C#代码：
C# code

public void close()
  {
  this.close();
  }