windows application to open website login button

public bool isrun;
        private void Form1_Load(object sender, EventArgs e)
        {
            webBrowser1.Url = new Uri("http://www.yourwebsite.com");
        }

        private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
        if(!isrun)
        {
            webBrowser1.Document.GetElementById("login_name").InnerText = "uid";
            webBrowser1.Document.GetElementById("passwd").InnerText = "pwd";
            webBrowser1.Document.GetElementById("buttonid_login").InvokeMember("click");      
           isrun=true;
        }

}