how to get age from birthday in facebook's PHPSDK.

fbBirthday_to_Age.php

//ユーザーの生年月日から年齢の取得
//アクセストークンの取得などは割愛

$birthday = $me -> birthday;
$birth = explode('/',$birthday);
$year = date("Y");$month = date("n");$day = date("j");//今日の日付
$b_month = $birth[0];
$b_day = $birth[1];
$age = $year - intval($birth[2]);

//月、日に桁埋めの０が含まれていたら取り除く
if(strstr($birth[0],'0',true) == ''){
	$b_month = intval(ltrim($birth[0],'0'));
}
if(strstr($birth[1],'0',true) == ''){
	$b_day = intval(ltrim($birth[1],'0'));
}

//年齢の計算
if($b_month > $month){
	$age = $age - 1;
}elseif($b_month === $month){
	if($b_day > $day){
		$age = $age - 1;
	}
}else{
	$age;
}