W3C Web Alarms API

This specification defines a System Level API to provide  access to the device alarm settings, which can schedule a  notification or for an application to be started at a specific  time. For example, some applications like alarm-clock, calendar  or auto-update might need to utilize Alarm API to trigger  particular device behaviors at specified time points.

Find out more on http://www.w3.org/TR/2013/WD-web-alarms-20130205/