ajax 비회원 글쓰기 문의드립니다.

<?php
include_once('./_common.php');

$wr_name = $_POST['wr_name'];
$wr_1 = $_POST['wr_1'];
$wr_email = $_POST['wr_email'];
$wr_homepage = $_POST['wr_homepage'];
$wr_content = $_POST['wr_content'];

$bo_table = $_POST['bo_table'];
$wr_subject = $_POST['wr_subject'];

$wr_id = $_POST['wr_id'];
$w = $_POST['w'];

if ($w == "") {
    // 새로운 글 등록인 경우
    $wr_password = generate_password(10);
    $wr_id = '';
    $mb_id = ''; // 비회원 글쓰기인 경우 mb_id를 비웁니다.
} else {
    // 글 수정인 경우
    $write = sql_fetch("SELECT * FROM {$g5['write_table']} WHERE wr_id = '{$wr_id}' ");
    if (!$write)
        alert("등록된 글이 없습니다.");
    
    $wr_password = $write['wr_password'];
    $mb_id = $write['mb_id'];
}

if (!trim($wr_name))
    alert("이름을 입력해주세요.");
if (!trim($wr_1))
    alert("연락처를 입력해주세요.");
if (!trim($wr_email))
    alert("이메일을 입력해주세요.");
if (!trim($wr_content))
    alert("문의내용을 입력해주세요.");

$wr_subject = get_text($wr_subject);
$wr_content = get_text($wr_content, 0, 1);

$sql_common = " wr_subject = '{$wr_subject}',
                wr_content = '{$wr_content}',
                wr_name = '{$wr_name}',
                wr_email = '{$wr_email}',
                wr_homepage = '{$wr_homepage}',
                wr_1 = '{$wr_1}',
                wr_password = '{$wr_password}',
                wr_datetime = '".G5_TIME_YMDHIS."',
                wr_last = '".G5_TIME_YMDHIS."' ";

if ($w == "") {
    // 새로운 글 등록인 경우
    $sql = "INSERT INTO {$g5['write_table']}
                SET {$sql_common} ";
} else if ($w == "u")