I have recently been playing around with some web development, targeting touch phones on the mobile web. For testing I fired you up my local iPhone simulator and Android emulator, launched the default browsers and tried to access localhost/127.0.0.1, to verify the progress of my development. In the iPhone simulator Safari served localhost/127.0.0.1 with a charm, but the browser on the Android emulator didn’t like it at all!

Since the Android emulator is simulating the entire underlying Linux based OS, localhost/127.0.0.1 is already used internally on the Android emulator, so for you being able to access the webapp at your localhost/127.0.0.1, you must replace localhost/127.0.0.1 with 10.0.2.2!

So all in all:
localhost/127.0.0.1 at the Android emulator = 10.0.2.2