user_guide_src/source/helpers/date_helper.rst - code-igniter-v3-giggi - Gitiles

 ###########
 Date Helper
 ###########

 The Date Helper file contains functions that help you work with dates.

 .. contents:: Page Contents

 Loading this Helper
 ===================

 This helper is loaded using the following code

 ::

 	$this->load->helper('date');

 The following functions are available:

 now()
 =====

 Returns the current time as a Unix timestamp, referenced either to your
 server's local time or GMT, based on the "time reference" setting in
 your config file. If you do not intend to set your master time reference
 to GMT (which you'll typically do if you run a site that lets each user
 set their own timezone settings) there is no benefit to using this
 function over PHP's time() function.

 .. php:method:: now()

 mdate()
 =======

 This function is identical to PHPs `date() <http://www.php.net/date>`_
 function, except that it lets you use MySQL style date codes, where each
 code letter is preceded with a percent sign: %Y %m %d etc.

 The benefit of doing dates this way is that you don't have to worry
 about escaping any characters that are not date codes, as you would
 normally have to do with the date() function. Example

 .. php:method:: mdate($datestr = '', $time = '')

 	:param string 	$datestr: Date String
 	:param integer 	$time: time
 	:returns: integer


 ::

 	$datestring = "Year: %Y Month: %m Day: %d - %h:%i %a";
 	$time = time();
 	echo mdate($datestring, $time);

 If a timestamp is not included in the second parameter the current time
 will be used.

 standard_date()
 ===============

 Lets you generate a date string in one of several standardized formats.
 Example

 .. php:method:: standard_date($fmt = 'DATE_RFC822', $time = '')

 	:param string 	$fmt: the chosen format
 	:param string 	$time: Unix timestamp
 	:returns: string

 ::

 	$format = 'DATE_RFC822';
 	$time = time();
 	echo standard_date($format, $time);

 The first parameter must contain the format, the second parameter must
 contain the date as a Unix timestamp.

 Supported formats:

 +----------------+------------------------+-----------------------------------+
 | Constant       | Description            | Example                           |
 +================+========================+===================================+
 | DATE_ATOM      | Atom                   | 2005-08-15T16:13:03+0000          |
 +----------------+------------------------+-----------------------------------+
 | DATE_COOKIE    | HTTP Cookies           | Sun, 14 Aug 2005 16:13:03 UTC     |
 +----------------+------------------------+-----------------------------------+
 | DATE_ISO8601   | ISO-8601               | 2005-08-14T16:13:03+00:00         |
 +----------------+------------------------+-----------------------------------+
 | DATE_RFC822    | RFC 822                | Sun, 14 Aug 05 16:13:03 UTC       |
 +----------------+------------------------+-----------------------------------+
 | DATE_RFC850    | RFC 850                | Sunday, 14-Aug-05 16:13:03 UTC    |
 +----------------+------------------------+-----------------------------------+
 | DATE_RFC1036   | RFC 1036               | Sunday, 14-Aug-05 16:13:03 UTC    |
 +----------------+------------------------+-----------------------------------+
 | DATE_RFC1123   | RFC 1123               | Sun, 14 Aug 2005 16:13:03 UTC     |
 +----------------+------------------------+-----------------------------------+
 | DATE_RFC2822   | RFC 2822               | Sun, 14 Aug 2005 16:13:03 +0000   |
 +----------------+------------------------+-----------------------------------+
 | DATE_RSS       | RSS                    | Sun, 14 Aug 2005 16:13:03 UTC     |
 +----------------+------------------------+-----------------------------------+
 | DATE_W3C       | W3C                    | 2005-08-14T16:13:03+0000          |
 +----------------+------------------------+-----------------------------------+


 local_to_gmt()
 ==============

 Takes a Unix timestamp as input and returns it as GMT.

 .. php:method:: local_to_gmt($time = '')

 	:param integer 	$time: Unix timestamp
 	:returns: string

 Example:

 ::

 	$now = time();
 	$gmt = local_to_gmt($now);

 gmt_to_local()
 ==============

 Takes a Unix timestamp (referenced to GMT) as input, and converts it to
 a localized timestamp based on the timezone and Daylight Saving time
 submitted.

 .. php:method:: gmt_to_local($time = '', $timezone = 'UTC', $dst = FALSE)

 	:param integer 	$time: Unix timestamp
 	:param string 	$timezone: timezone
 	:param boolean 	$dst: whether DST is active
 	:returns: integer

 Example

 ::

 	$timestamp = '1140153693';
 	$timezone  = 'UM8';
 	$daylight_saving = TRUE;
 	echo gmt_to_local($timestamp, $timezone, $daylight_saving);


 .. note:: For a list of timezones see the reference at the bottom of this page.


 mysql_to_unix()
 ===============

 Takes a MySQL Timestamp as input and returns it as Unix.

 .. php:method:: mysql_to_unix($time = '')

 	:param integer 	$time: Unix timestamp
 	:returns: integer

 Example

 ::

 	$mysql = '20061124092345';  $unix = mysql_to_unix($mysql);

 unix_to_human()
 ===============

 Takes a Unix timestamp as input and returns it in a human readable
 format with this prototype

 .. php:method:: unix_to_human($time = '', $seconds = FALSE, $fmt = 'us')

 	:param integer 	$time: Unix timestamp
 	:param boolean 	$seconds: whether to show seconds
 	:param string 	$fmt: format: us or euro
 	:returns: integer

 Example

 ::

 	YYYY-MM-DD HH:MM:SS AM/PM

 This can be useful if you need to display a date in a form field for
 submission.

 The time can be formatted with or without seconds, and it can be set to
 European or US format. If only the timestamp is submitted it will return
 the time without seconds formatted for the U.S. Examples

 ::

 	$now = time();
 	echo unix_to_human($now); // U.S. time, no seconds
 	echo unix_to_human($now, TRUE, 'us'); // U.S. time with seconds
 	echo unix_to_human($now, TRUE, 'eu'); // Euro time with seconds

 human_to_unix()
 ===============

 The opposite of the above function. Takes a "human" time as input and
 returns it as Unix. This function is useful if you accept "human"
 formatted dates submitted via a form. Returns FALSE (boolean) if the
 date string passed to it is not formatted as indicated above.

 .. php:method:: human_to_unix($datestr = '')

 	:param integer 	$datestr: Date String
 	:returns: integer

 Example:

 ::

 	$now = time();
 	$human = unix_to_human($now);
 	$unix = human_to_unix($human);

 nice_date()
 ===========

 This function can take a number poorly-formed date formats and convert
 them into something useful. It also accepts well-formed dates.

 The function will return a Unix timestamp by default. You can,
 optionally, pass a format string (the same type as the PHP date function
 accepts) as the second parameter.

 .. php:method:: nice_date($bad_date = '', $format = FALSE)

 	:param integer 	$bad_date: The terribly formatted date-like string
 	:param string 	$format: Date format to return (same as php date function)
 	:returns: string

 Example

 ::

 	$bad_time = 199605  // Should Produce: 1996-05-01
 	$better_time = nice_date($bad_time,'Y-m-d');
 	$bad_time = 9-11-2001 // Should Produce: 2001-09-11
 	$better_time = nice_date($human,'Y-m-d');

 timespan()
 ==========

 Formats a unix timestamp so that is appears similar to this

 ::

 	1 Year, 10 Months, 2 Weeks, 5 Days, 10 Hours, 16 Minutes

 The first parameter must contain a Unix timestamp. The second parameter
 must contain a timestamp that is greater that the first timestamp. If
 the second parameter empty, the current time will be used. The most
 common purpose for this function is to show how much time has elapsed
 from some point in time in the past to now.

 .. php:method:: timespan($seconds = 1, $time = '')

 	:param integer 	$seconds: a number of seconds
 	:param string 	$time: Unix timestamp
 	:returns: string

 Example

 ::

 	$post_date = '1079621429';
 	$now = time();
 	echo timespan($post_date, $now);

 .. note:: The text generated by this function is found in the following language
 	file: language/<your_lang>/date_lang.php

 days_in_month()
 ===============

 Returns the number of days in a given month/year. Takes leap years into
 account.

 .. php:method:: days_in_month($month = 0, $year = '')

 	:param integer 	$month: a numeric month
 	:param integer 	$year: a numeric year
 	:returns: integer

 Example

 ::

 	echo days_in_month(06, 2005);

 If the second parameter is empty, the current year will be used.

 timezones()
 ===========

 Takes a timezone reference (for a list of valid timezones, see the
 "Timezone Reference" below) and returns the number of hours offset from
 UTC.

 .. php:method:: timezones($tz = '')

 	:param string 	$tz: a numeric timezone
 	:returns: string

 Example

 ::

 	echo timezones('UM5');


 This function is useful when used with `timezone_menu()`.

 timezone_menu()
 ===============

 Generates a pull-down menu of timezones, like this one:


 .. raw:: html

 	<form action="#">
 		<select name="timezones">
 			<option value='UM12'>(UTC - 12:00) Enitwetok, Kwajalien</option>
 			<option value='UM11'>(UTC - 11:00) Nome, Midway Island, Samoa</option>
 			<option value='UM10'>(UTC - 10:00) Hawaii</option>
 			<option value='UM9'>(UTC - 9:00) Alaska</option>
 			<option value='UM8'>(UTC - 8:00) Pacific Time</option>
 			<option value='UM7'>(UTC - 7:00) Mountain Time</option>
 			<option value='UM6'>(UTC - 6:00) Central Time, Mexico City</option>
 			<option value='UM5'>(UTC - 5:00) Eastern Time, Bogota, Lima, Quito</option>
 			<option value='UM4'>(UTC - 4:00) Atlantic Time, Caracas, La Paz</option>
 			<option value='UM25'>(UTC - 3:30) Newfoundland</option>
 			<option value='UM3'>(UTC - 3:00) Brazil, Buenos Aires, Georgetown, Falkland Is.</option>
 			<option value='UM2'>(UTC - 2:00) Mid-Atlantic, Ascention Is., St Helena</option>
 			<option value='UM1'>(UTC - 1:00) Azores, Cape Verde Islands</option>
 			<option value='UTC' selected='selected'>(UTC) Casablanca, Dublin, Edinburgh, London, Lisbon, Monrovia</option>
 			<option value='UP1'>(UTC + 1:00) Berlin, Brussels, Copenhagen, Madrid, Paris, Rome</option>
 			<option value='UP2'>(UTC + 2:00) Kaliningrad, South Africa, Warsaw</option>
 			<option value='UP3'>(UTC + 3:00) Baghdad, Riyadh, Moscow, Nairobi</option>
 			<option value='UP25'>(UTC + 3:30) Tehran</option>
 			<option value='UP4'>(UTC + 4:00) Adu Dhabi, Baku, Muscat, Tbilisi</option>
 			<option value='UP35'>(UTC + 4:30) Kabul</option>
 			<option value='UP5'>(UTC + 5:00) Islamabad, Karachi, Tashkent</option>
 			<option value='UP45'>(UTC + 5:30) Bombay, Calcutta, Madras, New Delhi</option>
 			<option value='UP6'>(UTC + 6:00) Almaty, Colomba, Dhaka</option>
 			<option value='UP7'>(UTC + 7:00) Bangkok, Hanoi, Jakarta</option>
 			<option value='UP8'>(UTC + 8:00) Beijing, Hong Kong, Perth, Singapore, Taipei</option>
 			<option value='UP9'>(UTC + 9:00) Osaka, Sapporo, Seoul, Tokyo, Yakutsk</option>
 			<option value='UP85'>(UTC + 9:30) Adelaide, Darwin</option>
 			<option value='UP10'>(UTC + 10:00) Melbourne, Papua New Guinea, Sydney, Vladivostok</option>
 			<option value='UP11'>(UTC + 11:00) Magadan, New Caledonia, Solomon Islands</option>
 			<option value='UP12'>(UTC + 12:00) Auckland, Wellington, Fiji, Marshall Island</option>
 		</select>
 	</form>


 This menu is useful if you run a membership site in which your users are
 allowed to set their local timezone value.

 The first parameter lets you set the "selected" state of the menu. For
 example, to set Pacific time as the default you will do this

 .. php:method:: timezone_menu($default = 'UTC', $class = "", $name = 'timezones')

 	:param string 	$default: timezone
 	:param string	$class: classname
 	:param string	$name: menu name
 	:returns: string

 Example:

 ::

 	echo timezone_menu('UM8');

 Please see the timezone reference below to see the values of this menu.

 The second parameter lets you set a CSS class name for the menu.

 .. note:: The text contained in the menu is found in the following
 	language file: `language/<your_lang>/date_lang.php`


 Timezone Reference
 ==================

 The following table indicates each timezone and its location.

 +------------+----------------------------------------------------------------+
 | Time Zone  | Location                                                       |
 +============+================================================================+
 | UM12       | (UTC - 12:00) Enitwetok, Kwajalien                             |
 +------------+----------------------------------------------------------------+
 | UM11       | (UTC - 11:00) Nome, Midway Island, Samoa                       |
 +------------+----------------------------------------------------------------+
 | UM10       | (UTC - 10:00) Hawaii                                           |
 +------------+----------------------------------------------------------------+
 | UM9        | (UTC - 9:00) Alaska                                            |
 +------------+----------------------------------------------------------------+
 | UM8        | (UTC - 8:00) Pacific Time                                      |
 +------------+----------------------------------------------------------------+
 | UM7        | (UTC - 7:00) Mountain Time                                     |
 +------------+----------------------------------------------------------------+
 | UM6        | (UTC - 6:00) Central Time, Mexico City                         |
 +------------+----------------------------------------------------------------+
 | UM5        | (UTC - 5:00) Eastern Time, Bogota, Lima, Quito                 |
 +------------+----------------------------------------------------------------+
 | UM4        | (UTC - 4:00) Atlantic Time, Caracas, La Paz                    |
 +------------+----------------------------------------------------------------+
 | UM25       | (UTC - 3:30) Newfoundland                                      |
 +------------+----------------------------------------------------------------+
 | UM3        | (UTC - 3:00) Brazil, Buenos Aires, Georgetown, Falkland Is.    |
 +------------+----------------------------------------------------------------+
 | UM2        | (UTC - 2:00) Mid-Atlantic, Ascention Is., St Helena            |
 +------------+----------------------------------------------------------------+
 | UM1        | (UTC - 1:00) Azores, Cape Verde Islands                        |
 +------------+----------------------------------------------------------------+
 | UTC        | (UTC) Casablanca, Dublin, Edinburgh, London, Lisbon, Monrovia  |
 +------------+----------------------------------------------------------------+
 | UP1        | (UTC + 1:00) Berlin, Brussels, Copenhagen, Madrid, Paris, Rome |
 +------------+----------------------------------------------------------------+
 | UP2        | (UTC + 2:00) Kaliningrad, South Africa, Warsaw                 |
 +------------+----------------------------------------------------------------+
 | UP3        | (UTC + 3:00) Baghdad, Riyadh, Moscow, Nairobi                  |
 +------------+----------------------------------------------------------------+
 | UP25       | (UTC + 3:30) Tehran                                            |
 +------------+----------------------------------------------------------------+
 | UP4        | (UTC + 4:00) Adu Dhabi, Baku, Muscat, Tbilisi                  |
 +------------+----------------------------------------------------------------+
 | UP35       | (UTC + 4:30) Kabul                                             |
 +------------+----------------------------------------------------------------+
 | UP5        | (UTC + 5:00) Islamabad, Karachi, Tashkent                      |
 +------------+----------------------------------------------------------------+
 | UP45       | (UTC + 5:30) Bombay, Calcutta, Madras, New Delhi               |
 +------------+----------------------------------------------------------------+
 | UP6        | (UTC + 6:00) Almaty, Colomba, Dhaka                            |
 +------------+----------------------------------------------------------------+
 | UP7        | (UTC + 7:00) Bangkok, Hanoi, Jakarta                           |
 +------------+----------------------------------------------------------------+
 | UP8        | (UTC + 8:00) Beijing, Hong Kong, Perth, Singapore, Taipei      |
 +------------+----------------------------------------------------------------+
 | UP9        | (UTC + 9:00) Osaka, Sapporo, Seoul, Tokyo, Yakutsk             |
 +------------+----------------------------------------------------------------+
 | UP85       | (UTC + 9:30) Adelaide, Darwin                                  |
 +------------+----------------------------------------------------------------+
 | UP10       | (UTC + 10:00) Melbourne, Papua New Guinea, Sydney, Vladivostok |
 +------------+----------------------------------------------------------------+
 | UP11       | (UTC + 11:00) Magadan, New Caledonia, Solomon Islands          |
 +------------+----------------------------------------------------------------+
 | UP12       | (UTC + 12:00) Auckland, Wellington, Fiji, Marshall Island      |
 +------------+----------------------------------------------------------------+
	###########
	Date Helper
	###########

	The Date Helper file contains functions that help you work with dates.

	.. contents:: Page Contents

	Loading this Helper
	===================

	This helper is loaded using the following code

	::

	$this->load->helper('date');

	The following functions are available:

	now()
	=====

	Returns the current time as a Unix timestamp, referenced either to your
	server's local time or GMT, based on the "time reference" setting in
	your config file. If you do not intend to set your master time reference
	to GMT (which you'll typically do if you run a site that lets each user
	set their own timezone settings) there is no benefit to using this
	function over PHP's time() function.

	.. php:method:: now()

	mdate()
	=======

	This function is identical to PHPs `date() <http://www.php.net/date>`_
	function, except that it lets you use MySQL style date codes, where each
	code letter is preceded with a percent sign: %Y %m %d etc.

	The benefit of doing dates this way is that you don't have to worry
	about escaping any characters that are not date codes, as you would
	normally have to do with the date() function. Example

	.. php:method:: mdate($datestr = '', $time = '')

	:param string $datestr: Date String
	:param integer $time: time
	:returns: integer


	::

	$datestring = "Year: %Y Month: %m Day: %d - %h:%i %a";
	$time = time();
	echo mdate($datestring, $time);

	If a timestamp is not included in the second parameter the current time
	will be used.

	standard_date()
	===============

	Lets you generate a date string in one of several standardized formats.
	Example

	.. php:method:: standard_date($fmt = 'DATE_RFC822', $time = '')

	:param string $fmt: the chosen format
	:param string $time: Unix timestamp
	:returns: string

	::

	$format = 'DATE_RFC822';
	$time = time();
	echo standard_date($format, $time);

	The first parameter must contain the format, the second parameter must
	contain the date as a Unix timestamp.

	Supported formats:

	+----------------+------------------------+-----------------------------------+
	\| Constant \| Description \| Example \|
	+================+========================+===================================+
	\| DATE_ATOM \| Atom \| 2005-08-15T16:13:03+0000 \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_COOKIE \| HTTP Cookies \| Sun, 14 Aug 2005 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_ISO8601 \| ISO-8601 \| 2005-08-14T16:13:03+00:00 \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RFC822 \| RFC 822 \| Sun, 14 Aug 05 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RFC850 \| RFC 850 \| Sunday, 14-Aug-05 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RFC1036 \| RFC 1036 \| Sunday, 14-Aug-05 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RFC1123 \| RFC 1123 \| Sun, 14 Aug 2005 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RFC2822 \| RFC 2822 \| Sun, 14 Aug 2005 16:13:03 +0000 \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_RSS \| RSS \| Sun, 14 Aug 2005 16:13:03 UTC \|
	+----------------+------------------------+-----------------------------------+
	\| DATE_W3C \| W3C \| 2005-08-14T16:13:03+0000 \|
	+----------------+------------------------+-----------------------------------+


	local_to_gmt()
	==============

	Takes a Unix timestamp as input and returns it as GMT.

	.. php:method:: local_to_gmt($time = '')

	:param integer $time: Unix timestamp
	:returns: string

	Example:

	::

	$now = time();
	$gmt = local_to_gmt($now);

	gmt_to_local()
	==============

	Takes a Unix timestamp (referenced to GMT) as input, and converts it to
	a localized timestamp based on the timezone and Daylight Saving time
	submitted.

	.. php:method:: gmt_to_local($time = '', $timezone = 'UTC', $dst = FALSE)

	:param integer $time: Unix timestamp
	:param string $timezone: timezone
	:param boolean $dst: whether DST is active
	:returns: integer

	Example

	::

	$timestamp = '1140153693';
	$timezone = 'UM8';
	$daylight_saving = TRUE;
	echo gmt_to_local($timestamp, $timezone, $daylight_saving);


	.. note:: For a list of timezones see the reference at the bottom of this page.


	mysql_to_unix()
	===============

	Takes a MySQL Timestamp as input and returns it as Unix.

	.. php:method:: mysql_to_unix($time = '')

	:param integer $time: Unix timestamp
	:returns: integer

	Example

	::

	$mysql = '20061124092345'; $unix = mysql_to_unix($mysql);

	unix_to_human()
	===============

	Takes a Unix timestamp as input and returns it in a human readable
	format with this prototype

	.. php:method:: unix_to_human($time = '', $seconds = FALSE, $fmt = 'us')

	:param integer $time: Unix timestamp
	:param boolean $seconds: whether to show seconds
	:param string $fmt: format: us or euro
	:returns: integer

	Example

	::

	YYYY-MM-DD HH:MM:SS AM/PM

	This can be useful if you need to display a date in a form field for
	submission.

	The time can be formatted with or without seconds, and it can be set to
	European or US format. If only the timestamp is submitted it will return
	the time without seconds formatted for the U.S. Examples

	::

	$now = time();
	echo unix_to_human($now); // U.S. time, no seconds
	echo unix_to_human($now, TRUE, 'us'); // U.S. time with seconds
	echo unix_to_human($now, TRUE, 'eu'); // Euro time with seconds

	human_to_unix()
	===============

	The opposite of the above function. Takes a "human" time as input and
	returns it as Unix. This function is useful if you accept "human"
	formatted dates submitted via a form. Returns FALSE (boolean) if the
	date string passed to it is not formatted as indicated above.

	.. php:method:: human_to_unix($datestr = '')

	:param integer $datestr: Date String
	:returns: integer

	Example:

	::

	$now = time();
	$human = unix_to_human($now);
	$unix = human_to_unix($human);

	nice_date()
	===========

	This function can take a number poorly-formed date formats and convert
	them into something useful. It also accepts well-formed dates.

	The function will return a Unix timestamp by default. You can,
	optionally, pass a format string (the same type as the PHP date function
	accepts) as the second parameter.

	.. php:method:: nice_date($bad_date = '', $format = FALSE)

	:param integer $bad_date: The terribly formatted date-like string
	:param string $format: Date format to return (same as php date function)
	:returns: string

	Example

	::

	$bad_time = 199605 // Should Produce: 1996-05-01
	$better_time = nice_date($bad_time,'Y-m-d');
	$bad_time = 9-11-2001 // Should Produce: 2001-09-11
	$better_time = nice_date($human,'Y-m-d');

	timespan()
	==========

	Formats a unix timestamp so that is appears similar to this

	::

	1 Year, 10 Months, 2 Weeks, 5 Days, 10 Hours, 16 Minutes

	The first parameter must contain a Unix timestamp. The second parameter
	must contain a timestamp that is greater that the first timestamp. If
	the second parameter empty, the current time will be used. The most
	common purpose for this function is to show how much time has elapsed
	from some point in time in the past to now.

	.. php:method:: timespan($seconds = 1, $time = '')

	:param integer $seconds: a number of seconds
	:param string $time: Unix timestamp
	:returns: string

	Example

	::

	$post_date = '1079621429';
	$now = time();
	echo timespan($post_date, $now);

	.. note:: The text generated by this function is found in the following language
	file: language/<your_lang>/date_lang.php

	days_in_month()
	===============

	Returns the number of days in a given month/year. Takes leap years into
	account.

	.. php:method:: days_in_month($month = 0, $year = '')

	:param integer $month: a numeric month
	:param integer $year: a numeric year
	:returns: integer

	Example

	::

	echo days_in_month(06, 2005);

	If the second parameter is empty, the current year will be used.

	timezones()
	===========

	Takes a timezone reference (for a list of valid timezones, see the
	"Timezone Reference" below) and returns the number of hours offset from
	UTC.

	.. php:method:: timezones($tz = '')

	:param string $tz: a numeric timezone
	:returns: string

	Example

	::

	echo timezones('UM5');


	This function is useful when used with `timezone_menu()`.

	timezone_menu()
	===============

	Generates a pull-down menu of timezones, like this one:


	.. raw:: html

	<form action="#">
	<select name="timezones">
	<option value='UM12'>(UTC - 12:00) Enitwetok, Kwajalien</option>
	<option value='UM11'>(UTC - 11:00) Nome, Midway Island, Samoa</option>
	<option value='UM10'>(UTC - 10:00) Hawaii</option>
	<option value='UM9'>(UTC - 9:00) Alaska</option>
	<option value='UM8'>(UTC - 8:00) Pacific Time</option>
	<option value='UM7'>(UTC - 7:00) Mountain Time</option>
	<option value='UM6'>(UTC - 6:00) Central Time, Mexico City</option>
	<option value='UM5'>(UTC - 5:00) Eastern Time, Bogota, Lima, Quito</option>
	<option value='UM4'>(UTC - 4:00) Atlantic Time, Caracas, La Paz</option>
	<option value='UM25'>(UTC - 3:30) Newfoundland</option>
	<option value='UM3'>(UTC - 3:00) Brazil, Buenos Aires, Georgetown, Falkland Is.</option>
	<option value='UM2'>(UTC - 2:00) Mid-Atlantic, Ascention Is., St Helena</option>
	<option value='UM1'>(UTC - 1:00) Azores, Cape Verde Islands</option>
	<option value='UTC' selected='selected'>(UTC) Casablanca, Dublin, Edinburgh, London, Lisbon, Monrovia</option>
	<option value='UP1'>(UTC + 1:00) Berlin, Brussels, Copenhagen, Madrid, Paris, Rome</option>
	<option value='UP2'>(UTC + 2:00) Kaliningrad, South Africa, Warsaw</option>
	<option value='UP3'>(UTC + 3:00) Baghdad, Riyadh, Moscow, Nairobi</option>
	<option value='UP25'>(UTC + 3:30) Tehran</option>
	<option value='UP4'>(UTC + 4:00) Adu Dhabi, Baku, Muscat, Tbilisi</option>
	<option value='UP35'>(UTC + 4:30) Kabul</option>
	<option value='UP5'>(UTC + 5:00) Islamabad, Karachi, Tashkent</option>
	<option value='UP45'>(UTC + 5:30) Bombay, Calcutta, Madras, New Delhi</option>
	<option value='UP6'>(UTC + 6:00) Almaty, Colomba, Dhaka</option>
	<option value='UP7'>(UTC + 7:00) Bangkok, Hanoi, Jakarta</option>
	<option value='UP8'>(UTC + 8:00) Beijing, Hong Kong, Perth, Singapore, Taipei</option>
	<option value='UP9'>(UTC + 9:00) Osaka, Sapporo, Seoul, Tokyo, Yakutsk</option>
	<option value='UP85'>(UTC + 9:30) Adelaide, Darwin</option>
	<option value='UP10'>(UTC + 10:00) Melbourne, Papua New Guinea, Sydney, Vladivostok</option>
	<option value='UP11'>(UTC + 11:00) Magadan, New Caledonia, Solomon Islands</option>
	<option value='UP12'>(UTC + 12:00) Auckland, Wellington, Fiji, Marshall Island</option>
	</select>
	</form>


	This menu is useful if you run a membership site in which your users are
	allowed to set their local timezone value.

	The first parameter lets you set the "selected" state of the menu. For
	example, to set Pacific time as the default you will do this

	.. php:method:: timezone_menu($default = 'UTC', $class = "", $name = 'timezones')

	:param string $default: timezone
	:param string $class: classname
	:param string $name: menu name
	:returns: string

	Example:

	::

	echo timezone_menu('UM8');

	Please see the timezone reference below to see the values of this menu.

	The second parameter lets you set a CSS class name for the menu.

	.. note:: The text contained in the menu is found in the following
	language file: `language/<your_lang>/date_lang.php`


	Timezone Reference
	==================

	The following table indicates each timezone and its location.

	+------------+----------------------------------------------------------------+
	\| Time Zone \| Location \|
	+============+================================================================+
	\| UM12 \| (UTC - 12:00) Enitwetok, Kwajalien \|
	+------------+----------------------------------------------------------------+
	\| UM11 \| (UTC - 11:00) Nome, Midway Island, Samoa \|
	+------------+----------------------------------------------------------------+
	\| UM10 \| (UTC - 10:00) Hawaii \|
	+------------+----------------------------------------------------------------+
	\| UM9 \| (UTC - 9:00) Alaska \|
	+------------+----------------------------------------------------------------+
	\| UM8 \| (UTC - 8:00) Pacific Time \|
	+------------+----------------------------------------------------------------+
	\| UM7 \| (UTC - 7:00) Mountain Time \|
	+------------+----------------------------------------------------------------+
	\| UM6 \| (UTC - 6:00) Central Time, Mexico City \|
	+------------+----------------------------------------------------------------+
	\| UM5 \| (UTC - 5:00) Eastern Time, Bogota, Lima, Quito \|
	+------------+----------------------------------------------------------------+
	\| UM4 \| (UTC - 4:00) Atlantic Time, Caracas, La Paz \|
	+------------+----------------------------------------------------------------+
	\| UM25 \| (UTC - 3:30) Newfoundland \|
	+------------+----------------------------------------------------------------+
	\| UM3 \| (UTC - 3:00) Brazil, Buenos Aires, Georgetown, Falkland Is. \|
	+------------+----------------------------------------------------------------+
	\| UM2 \| (UTC - 2:00) Mid-Atlantic, Ascention Is., St Helena \|
	+------------+----------------------------------------------------------------+
	\| UM1 \| (UTC - 1:00) Azores, Cape Verde Islands \|
	+------------+----------------------------------------------------------------+
	\| UTC \| (UTC) Casablanca, Dublin, Edinburgh, London, Lisbon, Monrovia \|
	+------------+----------------------------------------------------------------+
	\| UP1 \| (UTC + 1:00) Berlin, Brussels, Copenhagen, Madrid, Paris, Rome \|
	+------------+----------------------------------------------------------------+
	\| UP2 \| (UTC + 2:00) Kaliningrad, South Africa, Warsaw \|
	+------------+----------------------------------------------------------------+
	\| UP3 \| (UTC + 3:00) Baghdad, Riyadh, Moscow, Nairobi \|
	+------------+----------------------------------------------------------------+
	\| UP25 \| (UTC + 3:30) Tehran \|
	+------------+----------------------------------------------------------------+
	\| UP4 \| (UTC + 4:00) Adu Dhabi, Baku, Muscat, Tbilisi \|
	+------------+----------------------------------------------------------------+
	\| UP35 \| (UTC + 4:30) Kabul \|
	+------------+----------------------------------------------------------------+
	\| UP5 \| (UTC + 5:00) Islamabad, Karachi, Tashkent \|
	+------------+----------------------------------------------------------------+
	\| UP45 \| (UTC + 5:30) Bombay, Calcutta, Madras, New Delhi \|
	+------------+----------------------------------------------------------------+
	\| UP6 \| (UTC + 6:00) Almaty, Colomba, Dhaka \|
	+------------+----------------------------------------------------------------+
	\| UP7 \| (UTC + 7:00) Bangkok, Hanoi, Jakarta \|
	+------------+----------------------------------------------------------------+
	\| UP8 \| (UTC + 8:00) Beijing, Hong Kong, Perth, Singapore, Taipei \|
	+------------+----------------------------------------------------------------+
	\| UP9 \| (UTC + 9:00) Osaka, Sapporo, Seoul, Tokyo, Yakutsk \|
	+------------+----------------------------------------------------------------+
	\| UP85 \| (UTC + 9:30) Adelaide, Darwin \|
	+------------+----------------------------------------------------------------+
	\| UP10 \| (UTC + 10:00) Melbourne, Papua New Guinea, Sydney, Vladivostok \|
	+------------+----------------------------------------------------------------+
	\| UP11 \| (UTC + 11:00) Magadan, New Caledonia, Solomon Islands \|
	+------------+----------------------------------------------------------------+
	\| UP12 \| (UTC + 12:00) Auckland, Wellington, Fiji, Marshall Island \|
	+------------+----------------------------------------------------------------+