1、使用PHP Mail函数发送Email

$to = "viralpatel.net@gmail.com";  
$subject = "VIRALPATEL.net";  
$body = "Body of your message here you can use HTML too. e.g. ﹤br﹥ ﹤b﹥ Bold ﹤/b﹥";  
$headers = "From: Peter\r\n";  
$headers .= "Reply-To: info@yoursite.com\r\n";  
$headers .= "Return-Path: info@yoursite.com\r\n";  
$headers .= "X-Mailer: PHP5\n";  
$headers .= 'MIME-Version: 1.0' . "\n";  
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";  
mail($to,$subject,$body,$headers);  
?﹥   
2、PHP中的64位编码和解码
function base64url_encode($plainText) {
$base64 = base64_encode($plainText);
$base64url = strtr($base64, '+/=', '-_,');
return $base64url;
}

function base64url_decode($plainText) {
$base64url = strtr($plainText, '-_,', '+/=');
$base64 = base64_decode($base64url);
return $base64;
} 
3、获取远程IP地址
function getRealIPAddr()
{
if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
{
$ip=$_SERVER['HTTP_CLIENT_IP'];
}
elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
{
$ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
}
else
{
$ip=$_SERVER['REMOTE_ADDR'];
}
return $ip;
}
4、 日期格式化
function checkDateFormat($date)
{
//match the format of the date
if (preg_match ("/^([0-9]{4})-([0-9]{2})-([0-9]{2})$/", $date, $parts))
{
//check weather the date is valid of not
if(checkdate($parts[2],$parts[3],$parts[1]))
return true;
else
return false;
}
else
return false;
}

5、验证Email

$email = $_POST['email'];
if(preg_match("~([a-zA-Z0-9!#$%&'*+-/=?^_`{|}~])@([a-zA-Z0-9-]).
                                 ([a-zA-Z0-9]{2,4})~",$email)) {
echo 'This is a valid email.';
} else{
echo 'This is an invalid email.';
}