编程时间长了，大家见过很多函数功能吧，比如获取用户IP等等，现在我将常用的PHP函数做个总结，方便大家COPY和使用。

<?php

//获取用户IP
function getIp()
{
    $ip = "";
    if (getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknow')) {
        $ip = getenv('HTTP_CLIENT_IP');
    } elseif (getenv('REMOTE_ADD') && strcasecmp(getenv('REMOTE_ADD'), 'unknow')) {
        $ip = getenv('REMOTE_ADD');
    } elseif (isset($_SERVER['REMOTE_ADDR']) && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknow')) {
        $ip = $_SERVER['REMOTE_ADDR'];
    }
    return $ip;
}

//快速替换字符串
//$arrayName = array('h'=>'s','o'=>'t','l'=>'xx');
//echo strsReplace('hello',$arrayName);
function strsReplace($str, $replaces)
{
    $subject=$str;
    foreach ($replaces as $k => $v)
        $subject = str_replace($k, $v, $subject);
    return $subject;
}

//规范文件名
//$filename='"<>/\\\asda/.,psd|"';
//echo tripFilename($filename);
function tripFilename($filename)
{
    //$s=array("/","\\","?","*","<",">",'"',"|",",","'");//使用时请删除屏蔽 
    return str_replace($s,"",$filename);
}

//PHP判断数组维度  
//$arr=array('yiyi'=>1212,'haha'=>array('heihei'=>array(array("a")),"b"));
//echo getMaxDim($arr);
function getMaxDim($vDim)
{
    if (!is_array($vDim))
        return 0;
    else {
        $max1 = 0;
        foreach ($vDim as $item1) {
            $t1 = getMaxDim($item1);
            if ($t1 > $max1)
                $max1 = $t1;
        }
        return $max1 + 1;
    }
}

//给数字加小数点,默认格式为452.00
//echo fee(452);
function fee($fee, $size = 2)
{
    $fee = trim($fee);
    if (empty($fee))
        return '0.00';
    if (!is_numeric($fee))
        return 'err';
    return number_format($fee, $size, '.', '');
}

//获取随机序列(注:实测数字最好9位一下)
//echo random(9,1);
//echo random(25);
function random($length, $numeric = 0)
{
    PHP_VERSION < '4.2.0' && mt_srand((double) microtime() * 100000000000);
    if ($numeric) {
        $hash = sprintf('%0' . $length . 'd', mt_rand(0, pow(10, $length) - 1));
    } else {
        $hash  = '';
        $chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz';
        $max   = strlen($chars) - 1;
        for ($i = 0; $i < $length; $i++) {
            $hash .= $chars[mt_rand(0, $max)];
        }
    }
    return $hash;
}

//错误提醒
function alertBack($msg = "")
{
    $html = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />
                   <script type=\"text/javascript\" charset=\"utf-8\">
                      alert('" . $msg . "');
                      window.history.back(-1);
                   </script>";
    echo $html;
    exit();
}

//提醒跳转
function alertGoto($url, $msg)
{
    $html = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />
                   <script type=\"text/javascript\" charset=\"utf-8\">
                      alert('" . $msg . "');
                      top.location = \"" . $url . "\";
                   </script>";
    echo $html;
    exit();
}

//建立文件夹
function createDir($path)
{
    if (!file_exists($path)) {
        createDir(dirname($path));
        mkdir($path);
    }
}

//删除文件夹
function deleteDir($dir)
{
    $dh = opendir($dir);
    while ($file = readdir($dh))
        if ($file != "." && $file != "..") {
            $fullpath = $dir . "/" . $file;
            if (!is_dir($fullpath))
                unlink($fullpath);
            else 
                deleteDir($fullpath);
        }
    closedir($dh);
    if (rmdir($dir))
        return true;
    else 
        return false;
}

//获取扩展名
function getFileType($filename)
{
    if (substr_count($filename, ".") == 0) { // 检查文件名中是否有.号。  
        return; // 返回空
    } else if (substr($filename, -1) == ".") { // 检查是否以.结尾，即无扩展名  
        return; // 返回空 
    } else {
        $fileType = strrchr($filename, "."); // 从.号处切割  
        $fileType = substr($fileType, 1); // 去除.号   
        return $fileType; // 返回  
    }
}

//匹配手机号
function checkTel($tel)
{
    if (strlen($tel) != 11)
        return false;
    return preg_match('/^1(3|5|8)[0-9]{9}$/', $tel);

}

//检查EMAIL格式
function checkEmail($email)
{
    if ($email == '')
        return false;
    if (eregi("^[_\.0-9a-z]+@([0-9a-z][0-9a-z]+\.)+[a-z]{2,3}$", $email))
        return true;
    return false;

}

//SMTP发送邮件
function sendMail($mail)
{
    global $m;
    if ($m->cfg['mailMethod'] == 'mail()') {
    }
    if ($m->cfg['mailMethod'] == 'smtp') {
        include_once "lib/smtp.class.php";
        $smtpserver  = $m->cfg['smtpServer']; //您的smtp服务器的地址 
        $port        = empty($m->cfg['smtpPort']) ? '25' : $m->cfg['smtpPort']; //smtp服务器的端口，一般是 25  
        $smtpuser    = $m->cfg['smtpCount']; //您登录smtp服务器的用户名 
        $smtppwd     = $m->cfg['smtpPas']; //您登录smtp服务器的密码 
        $mailtype    = "HTML"; //邮件的类型，可选值是 TXT 或 HTML ,TXT 表示是纯文本的邮件,HTML 表示是 html格式的邮件 
        $sender      = $m->cfg['smtpCount']; //发件人,一般要与您登录smtp服务器的用户名($smtpuser)相同,否则可能会因为smtp服务器的设置导致发送失败 
        $smtp        = new smtp($smtpserver, $port, true, $smtpuser, $smtppwd, $sender);
        $smtp->debug = true; //是否开启调试,只在测试程序时使用，正式使用时请将此行注释 
        $send        = $smtp->sendmail($mail['to'], $sender, $mail['subject'], $mail['body'], $mailtype);
        if ($send == 1)
            return true;
        return $this->smtp->logs;
    }
}

//检查身份证有效性
function checkId($id_card)
{
    if (strlen($id_card) == 18) {
        return idcard_checksum18($id_card);
    } elseif ((strlen($id_card) == 15)) {
        $id_card = idcard_15to18($id_card);
        return idcard_checksum18($id_card);
    } else {
        return false;
    }
}
// 计算身份证校验码，根据国家标准GB 11643-1999 
function idcard_verify_number($idcard_base)
{
    if (strlen($idcard_base) != 17) {
        return false;
    }
    //加权因子  
    $factor             = array(7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2);
    //校验码对应值  
    $verify_number_list = array('1','0','X','9','8','7','6','5','4','3','2');
    $checksum           = 0;
    for ($i = 0; $i < strlen($idcard_base); $i++) {
        $checksum += substr($idcard_base, $i, 1) * $factor[$i];
    }
    $mod           = $checksum % 11;
    $verify_number = $verify_number_list[$mod];
    return $verify_number;
}
// 将15位身份证升级到18位 
function idcard_15to18($idcard)
{
    if (strlen($idcard) != 15) {
        return false;
    } else {
        // 如果身份证顺序码是996 997 998 999，这些是为百岁以上老人的特殊编码  
        if (array_search(substr($idcard, 12, 3), array(
            '996',
            '997',
            '998',
            '999'
        )) !== false) {
            $idcard = substr($idcard, 0, 6) . '18' . substr($idcard, 6, 9);
        } else {
            $idcard = substr($idcard, 0, 6) . '19' . substr($idcard, 6, 9);
        }
    }
    $idcard = $idcard . idcard_verify_number($idcard);
    return $idcard;
}
// 18位身份证校验码有效性检查 
function idcard_checksum18($idcard)
{
    if (strlen($idcard) != 18) {
        return false;
    }
    $idcard_base = substr($idcard, 0, 17);
    if (idcard_verify_number($idcard_base) != strtoupper(substr($idcard, 17, 1))) {
        return false;
    } else {
        return true;
    }
}

//获取星期
//echo getWeek('2013-09-02');
function getWeek($day)
{
    $days = array('周日','周一','周二','周三','周四','周五','周六');
    $day  = explode('-', $day);
    return $days[date('w', mktime(0, 0, 0, $day[1], $day[2], $day[0]))];
}

?>