The function expects to be given a string containing an English date format
and will try to parse that format into a Unix timestamp (the number of
seconds since January 1 1970 00:00:00 UTC), relative to the timestamp given
in now, or the current time if
now is not supplied.
Each parameter of this function uses the default time zone unless a
time zone is specified in that parameter. Be careful not to use
different time zones in each parameter unless that is intended.
See date_default_timezone_get() on the various
ways to define the default time zone.
The timestamp which is used as a base for the calculation of relative
dates.
반환값
Returns a timestamp on success, FALSE otherwise. Previous to PHP 5.1.0,
this function would return -1 on failure.
오류/예외
모든 날짜/시간 함수 호출은
시간대가 유효하지 않을 때 E_NOTICE를, 시스템 설정이나
TZ 환경 변수를 사용할 때 E_STRICT나
E_WARNING 메세지를
생성합니다. date_default_timezone_set()을
참고하십시오.
변경점
버전
설명
5.3.0
Prior to PHP 5.3.0, relative time formats supplied to the
time argument of strtotime()
such as this week, previous week,
last week, and next week were
interpreted to mean a 7 day period relative to the current date/time, rather
than a week period of Monday through Sunday.
5.3.0
Prior to PHP 5.3.0, 24:00 was not a valid format and
strtotime() returned FALSE.
5.2.7
In PHP 5 prior to 5.2.7, requesting a given occurrence of a
given weekday in a month where that weekday was the first day
of the month would incorrectly add one week to the returned
timestamp. This has been corrected in 5.2.7 and later
versions.
5.1.0
Now returns FALSE on failure, instead
of -1.
5.1.0
시간대 오류시
E_STRICT와 E_NOTICE가
발생합니다.
5.0.2
In PHP 5 up to 5.0.2, "now" and other
relative times are wrongly computed from today's
midnight. This differs from other versions where it is
correctly computed from current time.
5.0.0
Microseconds began to be allowed, but they are ignored.
// previous to PHP 5.1.0 you would compare with -1, instead of false if (($timestamp = strtotime($str)) === false) { echo "The string ($str) is bogus"; } else { echo "$str == " . date('l dS \o\f F Y h:i:s A', $timestamp); } ?>
주의
Note:
If the number of the year is specified in a two digit format, the values
between 00-69 are mapped to 2000-2069 and 70-99 to 1970-1999. See the notes
below for possible differences on 32bit systems (possible dates might end on
2038-01-19 03:14:07).
Note:
The valid range of a timestamp is typically from Fri, 13 Dec
1901 20:45:54 UTC to Tue, 19 Jan 2038 03:14:07 UTC. (These are
the dates that correspond to the minimum and maximum values for
a 32-bit signed integer.)
Prior to PHP 5.1.0, not all platforms support negative timestamps, therefore
your date range may be limited to no earlier than the Unix epoch. This
means that e.g. dates prior to Jan 1, 1970 will not work on Windows,
some Linux distributions, and a few other operating systems.
For 64-bit versions of PHP, the valid range of a timestamp is effectively
infinite, as 64 bits can represent approximately 293 billion years in either
direction.
Note:
Dates in the m/d/y or d-m-y formats
are disambiguated by looking at the separator between the various
components: if the separator is a slash (/), then the
American m/d/y is assumed; whereas if the separator is a
dash (-) or a dot (.), then the
European d-m-y format is assumed.
If, however, the year is given in a two digit format and the separator is a
dash (-, the date string is parsed as
y-m-d.
To avoid potential ambiguity, it's best to use ISO 8601
(YYYY-MM-DD) dates or
DateTime::createFromFormat() when possible.