So I figure we can safely call this Project Carpool 1.0. It’s open for all to play with and can be found here: http://patang.org/projects/ajaxcarpool/carpool.php
Bug reports welcome as usual.
The project is now on the backburner, so future feature upgrades only on request (or as and when the fancy strikes me), so actually nothing really has changed except perhaps my blog might not be as monotonous as it had become while I was obsessing over this.
Thanks to everyone who chipped in with words of encouragement and bug reports. A shout out to Rajan for pointing me in the direction of XmlHttpRequest and making my life very interesting indeed. Special thanks also to Anoop, Anannya and Fadereu for helping test the application and for their insightful comments (‘Dude, the colours suck!’).