System.Windows.Forms.HtmlDocument does not contain a definition for GetElementByID
<p>Can you explain why I am receiving this error?</p>

<pre><code>    private void startButton_Click(object sender, EventArgs e)
    {
        HtmlElement mainNav = webBrowser1.Document.GetElementByID("home");
            mainNav.InvokeMember("click");
    }
</code></pre>

<p>Error 1</p>

<pre><code>'System.Windows.Forms.HtmlDocument' does not contain a definition for 'GetElementByID' and no extension method 'GetElementByID' accepting a first argument of type 'System.Windows.Forms.HtmlDocument' could be found (are you missing a using directive or an assembly reference?)
</code></pre>
