收藏PHP常用函数
最近研究PHP，收藏一下。
出处：php源码网-开源程序大全(Open Source)


内容：
<?
function GetIP() { //获取IP
if ($_SERVER["HTTP_X_FORWARDED_FOR"])
$ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
else if ($_SERVER["HTTP_CLIENT_IP"])
$ip = $_SERVER["HTTP_CLIENT_IP"];
else if ($_SERVER["REMOTE_ADDR"])
$ip = $_SERVER["REMOTE_ADDR"];
else if (getenv("HTTP_X_FORWARDED_FOR"))
$ip = getenv("HTTP_X_FORWARDED_FOR");
else if (getenv("HTTP_CLIENT_IP"))
$ip = getenv("HTTP_CLIENT_IP");
else if (getenv("REMOTE_ADDR"))
$ip = getenv("REMOTE_ADDR");
else
$ip = "Unknown";
return $ip;
}
?>

详细出处参考：http://www.jb51.net/article/22199.htm


<?php
function DateAdd($date, $int, $unit = "d") { //时间的增加（还可以改进成时分秒都可以增加，有时间再补上）
$dateArr = explode("-", $date);
$value[$unit] = $int;
return date("Y-m-d", mktime(0,0,0, $dateArr[1] + $value['m'], $dateArr[2] + $value['d'], $dateArr[0] + $value['y']));
}
function GetWeekDay($date) { //计算出给出的日期是星期几
$dateArr = explode("-", $date);
return date("w", mktime(0,0,0,$dateArr[1],$dateArr[2],$dateArr[0]));
}
?>
详细出处参考：http://www.jb51.net/article/22199.htm

<?
function check_date($date) { //检查日期是否合法日期
$dateArr = explode("-", $date);
if (is_numeric($dateArr[0]) && is_numeric($dateArr[1]) && is_numeric($dateArr[2])) {
return checkdate($dateArr[1],$dateArr[2],$dateArr[0]);
}
return false;
}
function check_time($time) { //检查时间是否合法时间
$timeArr = explode(":", $time);
if (is_numeric($timeArr[0]) && is_numeric($timeArr[1]) && is_numeric($timeArr[2])) {
if (($timeArr[0] >= 0 && $timeArr[0] <= 23) && ($timeArr[1] >= 0 && $timeArr[1] <= 59) && ($timeArr[2] >= 0 && $timeArr[2] <= 59))
return true;
else
return false;
}
return false;
}
详细出处参考：http://www.jb51.net/article/22199.htm


function DateDiff($date1, $date2, $unit = "") { //时间比较函数，返回两个日期相差几秒、几分钟、几小时或几天
switch ($unit) {
case 's':
$dividend = 1;
break;
case 'i':
$dividend = 60;
break;
case 'h':
$dividend = 3600;
break;
case 'd':
$dividend = 86400;
break;
default:
$dividend = 86400;
}
$time1 = strtotime($date1);
$time2 = strtotime($date2);
if ($time1 && $time2)
return (float)($time1 - $time2) / $dividend;
return false;
}
?>
详细出处参考：http://www.jb51.net/article/22199.htm


<?
方法一：header("Location: index.php");
方法二：echo "<scrīpt>window.location ="$PHP_SELF";</scrīpt>";
方法三：echo "<META HTTP-EQUIV="Refresh" CONTENT="0; URL=index.php">";
?>
详细出处参考：http://www.jb51.net/article/22199.htm

PHP重定向
复制代码 代码如下:
<?
方法一：header("Location: index.php");
方法二：echo "<scrīpt>window.location ="$PHP_SELF";</scrīpt>";
方法三：echo "<META HTTP-EQUIV="Refresh" CONTENT="0; URL=index.php">";
?>

获取访问者浏览器
代码如下:
<?
function browse_infor()
{
$browser="";$browserver="";
$Browsers =array("Lynx","MOSAIC","AOL","Opera","JAVA","MacWeb","WebExplorer","OmniWeb");
$Agent = $GLOBALS["HTTP_USER_AGENT"];
for ($i=0; $i<=7; $i++)
{
if (strpos($Agent,$Browsers[$i]))
{
$browser = $Browsers[$i];
$browserver ="";
}
}
if (ereg("Mozilla",$Agent) && !ereg("MSIE",$Agent))
{
$temp =explode("(", $Agent); $Part=$temp[0];
$temp =explode("/", $Part); $browserver=$temp[1];
$temp =explode(" ",$browserver); $browserver=$temp[0];
$browserver =preg_replace("/([d.]+)/","1",$browserver