Managing "return" in Callbacks

Managing "return" in Callbacks

When JQuery initiates an action (e.g. an Ajax PUT) it sets up a callback to handle processing the event when the time dependent action completes.  Since the callback operates as an independent thread, it cannot return to a calling routine via the "return" instruction.  Is there a way to preserve the context somehow to return to a calling routine?  Perhaps another type of callback event?