Web service using Google Maps JavaScript API

I'm trying to create a web service (.asmx) which takes bounding box parameters and also a geolocation. The intention is for the WS to return true/false depending on whether or not that geolocation is within the bounding box supplied.

I already know how to set up the web service and I know how to call the Google Map API but I can't see a way to do both in the same WS.

So my question is, can a web service be used together with the Google HTML/JavaScript API to do what I want?