Object receiver event looping on itself

if (searchSubmit == false)
            {
                webBrowser1.DocumentCompleted +=
                    new WebBrowserDocumentCompletedEventHandler(OnDocumentCompleted);
            }
            else
            {
                webBrowser1.Stop();
            }


        }
            
     private void OnDocumentCompleted(object receiver, WebBrowserDocumentCompletedEventArgs e)
        {
            HtmlElementCollection avCollection = webBrowser1.Document.GetElementById("filterAvailability").GetElementsByTagName("option");

            List<HtmlElement> avList = new List<HtmlElement>();
            foreach(HtmlElement avItem in avCollection)
            {
                avList.Add(avItem);
            }

            HtmlElement avElement =
                (HtmlElement)avList.Where(avOption => avOption.GetAttribute("value").Equals("1")).SingleOrDefault();

            if (avElement.GetAttribute("value").Equals("1"))
            {
                avElement.SetAttribute("Selected", "1");
                avElement.InvokeMember("click");
            }

            bookCollection = webBrowser1.Document.GetElementsByTagName("button");
            foreach (HtmlElement curElement in bookCollection)
            {
                if (curElement.GetAttribute("id").Equals("searchSubmit"))
                {
                    curElement.InvokeMember("click");
                }
            }
            searchSubmit = true;

         if (searchSubmit == true)
         {
             webBrowser1.Stop();
         }
        }