计算年龄算法（周岁虚岁）

    /**
    * $date是时间戳
    * $type为1的时候是虚岁,2的时候是周岁
    */
    function getAgeByBirth($date,$type = 1){
      $nowYear = date("Y",time());
      $nowMonth = date("m",time());
      $nowDay = date("d",time());
      $birthYear = date("Y",$date);
      $birthMonth = date("m",$date);
      $birthDay = date("d",$date);
      if($type == 1){
        $age = $nowYear - ($birthYear - 1);
      }else{$type == 2}{
        if($nowMonth<$birthMonth){
          $age = $nowYear - $birthYear - 1;
        }elseif($nowMonth==$birthMonth){
          if($nowDay<$birthDay){
            $age = $nowYear - $birthYear - 1;
          }else{
            $age = $nowYear - $birthYear;
          }
        }else{
          $age = $nowYear - $birthYear;
        }
      }
      return $age;
    }