I have a code to get the all html source into a richtextbox but I need display only the body text. Can you help me?

This is the code to get the source:

Code:
Try
            Dim request As System.Net.HttpWebRequest = System.Net.HttpWebRequest.Create(TextBoxurlseochecker.Text)
            Dim response As System.Net.HttpWebResponse = request.GetResponse()

            Dim sr As System.IO.StreamReader = New System.IO.StreamReader(response.GetResponseStream())

            Dim sourcecode As String = sr.ReadToEnd()

            RichTextBoxseochecker.Text = sourcecode
        Catch ex As Exception

        End Try