How do I get the inventory available for a specific item in a specific location via script?

Currently, I am just showing the total inventory everywhere using this:
var quantityAvailable = "<%=getCurrentAttribute('item','quantityavailable' )%>";

However, we have certain locations that we don't want to ship from if we sell things online, so I have to limit our quantity showing to only certain locations, not the entire amount available.

Thanks!
Paul