Both of the holidays occur in the lunar based Islamic calendar which is different from the solar based Gregorian calendar. The Islamic calendar is based on the synodic period of the Moon's revolution around the Earth, approximately 291⁄2 days. The Islamic calendar alternates months of 29 and 30 days (which begin with the new moon). Twelve of these months make up an Islamic year, which is 11 days shorter than the Gregorian year. The Gregorian calendar is based on the orbital period of the Earth's revolution around the Sun, approximately days.
This page contains all about Islamic Holiday Quotes.