// Simply:
$date = date('Y-m-d H:i:s');

// Or:
$date = date('Y/m/d H:i:s');

// This would return the date in the following formats respectively:
$date = '2012-03-06 17:33:07';
// Or
$date = '2012/03/06 17:33:07';

/** 
 * This time is based on the default server time zone.
 * If you want the date in a different time zone,
 * say if you come from Nairobi, Kenya like I do, you can set
 * the time zone to Nairobi as shown below.
 */

date_default_timezone_set('Africa/Nairobi');

// Then call the date functions
$date = date('Y-m-d H:i:s');
// Or
$date = date('Y/m/d H:i:s');

// date_default_timezone_set() function is however
// supported by PHP version 5.1.0 or above.

有关时区参考，请参见支持的时区列表。

PHP的time()返回当前Unix时间戳。这样，您就可以使用date()函数将其格式化为您需要的格式。

$date = date('Format String', time());

正如Paolo在评论中提到的，第二个论点是多余的。下面的代码段相当于上面的代码段:

$date = date('Format String');

PHP的date函数可以完成这项工作。

日期()

描述:

string date(string $format [, int $timestamp = time()])

返回根据给定格式字符串使用给定整数时间戳格式化的字符串，如果没有给出时间戳则返回当前时间。

例子:

$today = date("F j, Y, g:i a");               // March 10, 2001, 5:16 pm
$today = date("m.d.y");                       // 03.10.01
$today = date("j, n, Y");                     // 10, 3, 2001
$today = date("Ymd");                         // 20010310
$today = date('h-i-s, j-m-y, it is w Day');   // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.'); // it is the 10th day.
$today = date("D M j G:i:s T Y");             // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h');   // 17:03:18 m is month
$today = date("H:i:s");                       // 17:16:18
$today = date("Y-m-d H:i:s");                 // 2001-03-10 17:16:18 (the MySQL DATETIME format)

我们可以使用date函数设置默认时区:

<?php
    date_default_timezone_set("Asia/Kolkata");
    echo "Today is " . date("Y/m/d") . "<br>";
    echo "Today is " . date("Y.m.d") . "<br>";
    echo "Today is " . date("Y-m-d") . "<br>";
    echo "Today is " . date("l");
    echo "The time is " . date("h:i:sa");
?>

使用date()和DateTimeInterface::format格式化日期，即date('Y-m-d H:i:s');，你有这些可选格式:

来源:DateTimeInterface:::格式页面。

echo date("d-m-Y H:i:sa");

这段代码将获得运行该代码的服务器的日期和时间。