The calendar form field type provides a text box for entry of a date. An icon next to the text box provides a link to a pop-up calendar, which can also be used to enter the date value. If the field has a saved value this is shown in the text box. Otherwise the default value, if any, is displayed.
Example XML Field Definition:
label="Select a date"
type - must be calendar.
name - is the unique name of the field.
label - (translatable) is the descriptive title of the field.
default is the default date. You can put "NOW" to have current date or time information in the given format.
description (translatable) is text that will be shown as a tool tip when the user moves the mouse over the text box.
readonly is whether the text box is read-only (true or false). If the text box is read-only, the date cannot be changed, but can be selected and copied. No calendar icon will be shown.
disabled is whether the text box is disabled (true or false). If the text box is disabled, the date cannot be changed, selected or copied.
class is a CSS class name for the HTML form field.
format is the date format to be used. This is in the format used by PHP to specify date string formats. If no format argument is given, '%Y-%m-%d' is assumed.
filter is time zone to be used. There are two values; server_utc and user_utc. The first one is server time zone and the later is user time zone as configured in global configuration and user information respectively.
translateformat: If set to true, the calendar will use a language string to determine the format. The `format` attribute is ignored. If false, the `format` attribute is used (same behaviour as today).
showtime: If set to true and translateformat is true, the language key DATE_FORMAT_CALENDAR_DATETIME is used, otherwise DATE_FORMAT_CALENDAR_DATE.
timeformat: can be set to 12 (and specify AM or PM) or 24
singleheader: if set to false, the year and the month selection will be set on two separates lines, with independent selection
todaybutton: if set to true, a button is added at the bottom of the datePicker to select the date of the current day
weeknumbers: if set to true, a column is added at the left of the datePicker to display the number of the week in the current year
filltable: if set to true, dates of the previous and next month is added at the top and the bottom of the current month to fill the grid
minyear: set a signed integer for a number of years (-10, -2, 0, 7, 12, ...) to define the relative lower limit for the year selection. The user could not select a year before your limit
maxyear: set a signed integer for a number of years (-10, -2, 0, 7, 12, ...) to define the relative upper limit for the year selection. The user could not select a year after your limit
The format attribute specifies the format that the date string will be saved in. It is also the format that manually entered dates need to be entered in.