Javascript arrays of day and month names, short and long as well as an array of the number of days in each month.

days.js

//long
var DAYS = [
  'Sunday',
  'Monday',
  'Tuesday',
  'Wednesday',
  'Thursday',
  'Friday',
  'Saturday'];

//short
var DAYS = [
  'Sun',
  'Mon',
  'Tue',
  'Wed',
  'Thu',
  'Fri',
  'Sat'];

months.js

 //short
 var MONTHS = [
  'January',
  'February',
  'March',
  'April',
  'May',
  'June',
  'July',
  'August',
  'September',
  'October',
  'November',
  'December'];

//long
 var MONTHS = [
  'Jan',
  'Feb',
  'Mar',
  'Apr',
  'May',
  'Jun',
  'Jul',
  'Aug',
  'Sep',
  'Oct',
  'Nov',
  'Dec'];
  
//days in months
DAYS_IN_MONTH = [
  31,
  28,
  31,
  30,
  31,
  30,
  31,
  31,
  30,
  31,
  30,
  31];