You have got it perfectly right KillerKev.
With the 3rd paramter set to false, the request is made synchronously, and that's why the onreadystatechange is not needed.

When doen asynchronously, the request is fired inbackground and more or less "forgot".
The onreadystatechange is there to get feedback and catch teh datas back.

In a synchronous mode, there is no need to watch the state, therefor the lack of return handler function.