/**     * @param $idcard     * @return bool     * 判断身份证格式     */    function is_idcard($idcard){        $id = strtoupper($idcard);        $regx = "/(^\d{15}$)|(^\d{17}([0-9]|X)$)/";        $arr_split = array();        if(!preg_match($regx, $id))        {            return FALSE;        }        if(15 == strlen($id)) //检查15位        {            $regx = "/^(\d{6})+(\d{2})+(\d{2})+(\d{2})+(\d{3})$/";            @preg_match($regx, $id, $arr_split);            //检查生日日期是否正确            $dtm_birth = "19".$arr_split[2] . '/' . $arr_split[3]. '/' .$arr_split[4];            if(!strtotime($dtm_birth))            {                return FALSE;            } else {                return TRUE;            }        }        else      //检查18位        {            $regx = "/^(\d{6})+(\d{4})+(\d{2})+(\d{2})+(\d{3})([0-9]|X)$/";            @preg_match($regx, $id, $arr_split);            $dtm_birth = $arr_split[2] . '/' . $arr_split[3]. '/' .$arr_split[4];            if(!strtotime($dtm_birth)) //检查生日日期是否正确            {                return FALSE;            }            else            {                //检验18位身份证的校验码是否正确。                //校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。                $arr_int = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);                $arr_ch = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');                $sign = 0;                for ( $i = 0; $i < 17; $i++ )                {                    $b = (int) $id{$i};                    $w = $arr_int[$i];                    $sign += $b * $w;                }                $n = $sign % 11;                $val_num = $arr_ch[$n];                if ($val_num != substr($id,17, 1))                {                    return FALSE;                }else{                    return TRUE;                }            }        }    }