PHP项目开发中最常用的自定义函数整理

　　<?php
//alert提示
function alert($msg){
echo <script>alert($msg);</script>;
}
//把一些预定义的字符转换为 HTML 实体
function d_htmlspecialchars($string) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = d_htmlspecialchars($val);
}
} else {
$string = str_replace(&, , $string);
$string = str_replace(, ", $string);
$string = str_replace(, ', $string);
$string = str_replace(<, <, $string);
$string = str_replace(>, >, $string);
$string = preg_replace(/(#\d;)/, &\1, $string);
}
return $string;
}
//在预定义字符前加上反斜杠，包括 单引号、双引号、反斜杠、NULL，以保护数据库安全
function d_addslashes($string, $force = 0) {
if(!$GLOBALS[magic_quotes_gpc] $force) {
if(is_array($string)) {
foreach($string as $key => $val) $string[$key] = d_addslashes($val, $force);
}
else $string = addslashes($string);
}
return $string;
}
//生成随机字符串，包含大写、小写字母、数字
function randstr($length) {
$hash = ;
$chars = ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz;
$max = strlen($chars) - 1;
mt_srand((double)microtime() * 1000000);
for($i = 0; $i < $length; $i++) {
$hash .= $chars[mt_rand(0, $max)];
}
return $hash;
}
//转换时间戳为常用的日期格式
function trans_time($timestamp){
if($timestamp < 1) echo 无效的Unix时间戳;
else return date(Y-m-d H:i:s,$timestamp);
}
//获取IP
function get_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 $ip;
}
//计算时间差：默认返回类型为“分钟”
//$old_time 只能是时间戳，$return_type 为 h 是小时，为 s 是秒
function timelag($old_time,$return_type=m){
if($old_time < 1){
echo 无效的Unix时间戳;
}else{
switch($return_type){
case h:
$type = 3600; break;
case m:
$type = 60; break;
case s:
$type = 1; break;
case :
$type = 60; break;
}
$dif = round( (time()-$old_time)/$type ) ;
return $dif;
}
}
//获取当前页面的URL地址
function url_this(){
$url =
$return_url = <a href=$url>$url</a>;
return $return_url;
}
//跳转函数
function url_redirect($url,$delay=){
if($delay == ){
echo <script>window.location.href=$url</script>;
}else{
echo <meta http-equiv=refresh content=$delay;URL=$url />;
}
}
} //end func

?>