js-cal

calendar(true)(2016, 8); //use monday as first day of week = true, year = 2016, month = 8 (September)

[ 
  [ null, null, null, 1, 2, 3, 4 ],
  [ 5, 6, 7, 8, 9, 10, 11 ],
  [ 12, 13, 14, 15, 16, 17, 18 ],
  [ 19, 20, 21, 22, 23, 24, 25 ],
  [ 26, 27, 28, 29, 30, null, null ] 
]