private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            HtmlElement name = webBrowser1.Document.GetElementById("username");
            if (name != null)
                 name.SetAttribute("value", "superman");
            HtmlElement pass = webBrowser1.Document.GetElementById("psw");
             if (pass != null)
                 pass.SetAttribute("value", "a1b2c3");
             
            HtmlElementCollection hecs=webBrowser1.Document.GetElementsByTagName("input");
            
            foreach( HtmlElement hec in hecs)
            {
                if(hec.Name=="Submit")
                {
                    
                    HtmlElement login = hec;
                    if (login != null)
                    login.InvokeMember("click");

                }
            }


        }