Monkeybread Xojo plugin

Answer: Use the Webpage.ParametersReceived event.

Example

Sub ParametersReceived(Variables As Dictionary)
  for each key as Variant in Variables.keys
    MsgBox key+" -> "+Variables.Value(key)
  next
End Sub

The text encodings of this strings is not defined in Xojo 2010r5. Please use DefineEncoding.