Automating an embedded browser

I have an embedded browser application that is in development to log users into known websites. I have the name and the password fields filling out ok, but I need to submit the form from there by either automatically clicking the submit button or having the application submit the form to continue.  Below is my current code. I tried converting the HTMLelement to a Button but it is not allowed.




        private void atgLoginButton_Click(object sender, EventArgs e)
        {

            HtmlDocument doc = webBrowser1.Document;

            HtmlElement nameElement = doc.GetElementById("tb");
            HtmlElement passElement = doc.GetElementById("tbxPass");
            HtmlElement buttonElement = doc.GetElementById("btnLogIn");

            nameElement.InnerText = "XXXXXX";
            passElement.InnerText = "XXXXXX";
 
        }