[OPEN-ILS-GENERAL] Custom client possible?

[bookworm2010]

Is it possible for an end user (i.e. member of the public) to write his own 
client to query the library catalog instead of using the OPAC? If so what are 
the related resources (documentation, sample code, forum/email list, etc)? The 
ideal solution would be a set of js functions for making queries, placing hold, 
logging in, retrieving patron's record, etc. Thx.