how to give parameters in url for getting json parse for both taxonomy terms AND nodes
you can use taxonomy_select_nodes to find all nodes associated with a term.

Return nodes attached to a term across all field instances.

Parameters

$tid: The term ID.

$pager: Boolean to indicate whether a pager should be used.

$limit: Integer. The maximum number of nodes to find. Set to FALSE for no limit.

$order: An array of fields and directions.

API