shawnchin/jquery-cron — pull request #2 by tfforums (2011-10-11 03:36:02+00:00)
Title: extraValues

extraValues:[["5 Minutes","*/5 * * * *"],["15 Minutes","*/15 * * * *"]] for addition into the initial list.

added this as a config option... had some troubles wtih the initial onchange of the select value (if i specified and onChange option, the fuction would always have the old values)

may want to start with this and add a 'custom' period option instead of just putting these directly into the initial one.