取得客户端ip地址 
<?
//开源代码
function getip(){ 
             if (getenv("http_client_ip") && strcasecmp(getenv("http_client_ip"), "unknown")) 
$ip = getenv("http_client_ip"); //开源 
             else if (getenv("http_x_forwarded_for") && strcasecmp(getenv("http_x_forwarded_for"), "unknown")) 
$ip = getenv("http_x_forwarded_for"); // 
             else if (getenv("remote_addr") && strcasecmp(getenv("remote_addr"), "unknown")) 
$ip = getenv("remote_addr"); 
             else if (isset($_server[@#remote_addr@#]) && $_server[@#remote_addr@#] && strcasecmp($_server[@#remote_addr@#], "unknown"))
//
$ip = $_server[@#remote_addr@#]; 
else 
$ip = "unknown"; 
             return($ip); 
} 

判断邮箱地址 
<? 
function checkemail($inaddress) 
{ 
return (ereg("^([a-za-z0-9_-])+@([a-za-z0-9_-])+(.[a-za-z0-9_-])+",$inaddress)); 
} 

<? 
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; 
} 

文章网址:http://www.phprm.com/code/37100.html

随意转载^^但请附上教程地址。