Accepts the following characters for date formatting: d, D, j, l, N, w, S, F, m, M, n, Y, y, h, H, g, G, i, s, a, A, borrowing the syntax from PHP's
date function. If format property contains time-related characters (g, G, h, H, i, s, a, A), the time picker will be automatically enabled. Note that when setting a date format without days (d, j), the users will be able to select only years and months, and when setting a format without months and days (F, m, M, n, t, d, j), the users will be able to select only years. Similarly, setting a format that contains only time-related characters, will result in users being able to only select time.