计算出生年月转成年龄

    	$birth='1972-9-18'; 
		list($by,$bm,$bd)=explode('-',$birth); 
		$cm=date('n'); 
		$cd=date('j'); 
		$age=date('Y')-$by-1; 
		if ($cm>$bm || $cm=$bm && $cd>$$bd) $age++; 
		echo "生日:$birth\n年龄:$age\n";