We have a site that was scraping a site to gather all models available of a product. The 3rd party site recently changed the website so it now uses ajax for users to select the manufacturer and then once they select that it loads a dropdown with products using ajax.

I currently was using httpwebrequest for all requests (see below).
Code:
Public Function fnRequest(ByVal sPOSTData As String, Optional ByVal bAutoRedirect As Boolean = False) As String
        Dim uriSite As Uri
        Dim sReturn As String
        Dim srReader As StreamReader
        Dim sTemp As String

        sReturn = String.Empty
        Try
            ' Setup request
            uriSite = New Uri(m_sURL)
            m_hwrRequest = DirectCast(WebRequest.Create(uriSite), HttpWebRequest)
            m_hwrRequest.Referer = m_sReferer
            m_hwrRequest.UserAgent = m_sUserAgent
            m_hwrRequest.AllowAutoRedirect = bAutoRedirect
            m_hwrRequest.AllowWriteStreamBuffering = True
            m_hwrRequest.KeepAlive = False
            m_hwrRequest.Accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-powerpoint, application/vnd.ms-excel, application/msword, application/x-shockwave-flash, */*"

            If Not (m_ccCookies Is Nothing) Then
                If m_ccCookies.Count > 0 Then
                    m_hwrRequest.CookieContainer = New CookieContainer()
                    m_hwrRequest.CookieContainer.Add(m_ccCookies)
                End If
            End If
            
            If Not (sPOSTData Is Nothing) AndAlso sPOSTData.Length > 0 Then
                Dim stWS As Stream
                Dim aeEnc As ASCIIEncoding
                Dim baBuf As Byte()

                aeEnc = New ASCIIEncoding()
                baBuf = aeEnc.GetBytes(sPOSTData)

                m_hwrRequest.Method = "POST"
                m_hwrRequest.ContentLength = baBuf.Length
                m_hwrRequest.ContentType = "application/x-www-form-urlencoded"

                stWS = m_hwrRequest.GetRequestStream()
                stWS.Write(baBuf, 0, baBuf.Length)
                stWS.Close()
                'm_hwrRequest.AllowAutoRedirect = True
            End If

            m_hwrResponse = DirectCast(m_hwrRequest.GetResponse(), HttpWebResponse)

            srReader = New StreamReader(m_hwrResponse.GetResponseStream())
            sReturn = srReader.ReadToEnd()
            srReader.Close()

            '------------------------------------------------------------------
            ' capture the redirect location from the header
            '------------------------------------------------------------------
            Try
                Dim wbHCol As WebHeaderCollection = m_hwrResponse.Headers
                Dim i As Integer
                For i = 0 To wbHCol.Count - 1

                    Dim header As String = wbHCol.GetKey(i)
                    Dim values As String() = wbHCol.GetValues(header)

                    If values.Length > 0 AndAlso header.ToLower = "location" Then
                        Location1 &= values(0)
                    End If
                Next
            Catch
                Location1 = String.Empty
            End Try
            '------------------------------------------------------------------

            If Not m_hwrResponse.Headers("Set-Cookie") Is Nothing Then
                Dim ccContainer As New CookieContainer()

                ccContainer = New CookieContainer()
                ccContainer.SetCookies(m_hwrResponse.ResponseUri, m_hwrResponse.Headers("Set-Cookie"))
                sTemp = m_hwrResponse.Headers("Set-Cookie").ToString
                m_ccCookies.Add(ccContainer.GetCookies(m_hwrResponse.ResponseUri))
            End If

            Me.Referer = m_hwrResponse.ResponseUri.AbsoluteUri

            'close response connection
            m_hwrResponse.Close()

        Catch ex As Exception
            lblError.Text &= ex.Message.ToString
        End Try

        Return sReturn
    End Function
#End Region
Now in fiddler the post appears to be done with ajax. I tried to send the post data the normal way but it didn't like that.

Does anyone have an example of how to do this? To get an idea go to http://www.chiefmfg.com/ and see Mount finder and select Projector.

Thanks to any info in advance.