x404

$link = mysqli_connect('localhost', '', '',
    'test') or die('Could not connect: '.mysqli_error());
$query = "SELECT * FROM `categories`";
$query1 = "SELECT * FROM `locations` l INNER JOIN `categories` c ON c.category_key=l.key_i WHERE 1";
$query2 = "SELECT * FROM `levels`";
$result = mysqli_query($link, $query) or die('Query failed: '.mysqli_error());
$result1 = mysqli_query($link, $query1) or die('Query failed: '.mysqli_error());
$result2 = mysqli_query($link, $query2) or die('Query failed: '.mysqli_error());

$response = [
    'mapwidth' => 1000,
    'mapheight' => 600,
    'categories' => [],
    'levels' => [],
];

while ($category = mysqli_fetch_object($result)) {
    $response['categories'][] = [
        'title' => $category->title_c,
    ];
}

while ($level = mysqli_fetch_object($result2)) {
    $response['levels'][$level->levels_key] = [
        'title' => $level->title_i,
        'map' => $level->map_i,
    ];
}

var_dump($result1);

while ($location = mysqli_fetch_object($result1)) {
    echo $location->key_i;
    $response['levels'][$location->key_i]['locations'][] = [
        'title' => $location->title_l,
        'about' => $location->about_l,
        'category' => $location->title_c,
    ];
}

file_put_contents("chart_data.json", json_encode($response, JSON_UNESCAPED_UNICODE));

echo json_encode($response, JSON_PRETTY_PRINT);

var json = [{'id':1, 'name':'John', 'collection':'boston'},
{'id':2, 'name':'Faer', 'collection':'antler'},
{'id':3, 'name':'klei', 'collection':'aqua'},
{'id':4, 'name':'Inda', 'collection':'boston'},
{'id':5, 'name':'Faer', 'collection':'antler'}];

var result = new Set();

for (var i = 0; i < json.length; i++) {
    result.add(json[i].collection);
}

console.log(result);

WHERE name LIKE '%$search_q%' OR author LIKE '%$search_q%'

1. Использовать SMTP, например через либу - PHPMailer
   
2. Не палить email админа

   <input type="hidden" name="admin_email" value="admin@gmail.com">