what is timestamp in php

The timestamp refers to the total number of seconds from Greenwich Mean Time on January 1, 1970 (00:00:00 GMT) to the current time. It is also called Unix Timestamp.

PHP provides functions that can easily convert various forms of dates into timestamps. The main functions of this type are:

strtotime(): Convert the date and time of any English text The description resolves to a timestamp.

mktime(): Get timestamp from date.

strtotime()

strtotime() function is used to convert the date represented by the English text string into a timestamp. It is the inverse function of date(). It returns a timestamp successfully, otherwise it returns FALSE. . Syntax:

int strtotime ( string time [, int now] )

The parameter time is the parsed string, which is the date represented according to the GNU date input format.

Example:

<?php
echo strtotime("2009-10-21 16:00:10");	//输出 1256112010
echo strtotime("10 September 2008");	//输出 1220976000
echo strtotime("+1 day"), "<br />";	//输出明天此时的时间戳
?>

mktime()

mktime() function is used to get the timestamp from the date, and returns the timestamp successfully, otherwise it returns FALSE. Syntax:

int mktime(时, 分, 秒, 月, 日, 年)

For example

<?php
echo mktime(21, 50, 55, 07, 14, 2010);		//输出“1279115455”
?>

Parameters can be omitted from right to left, and any omitted parameters will be set to the current value of the local date and time.

mktime() is useful for doing date calculations and validation, it will automatically calculate the correct value for out-of-range input.

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