Q:

Check the latitude and longitude of user on form

I'm a beginner in PHP.
I have a problem in a form, i have to verify if the user is sending me an adress of Paris or not.
<?php
    $msg="";
    $db = mysqli_connect("localhost", "root", "", "dbname");
    if (isset($_FILES["image"]) AND !empty($_FILES['image']['name']))
    {
        $tailleMax = 3097152;
        $extensionsValides = array('jpg', 'jpeg', 'png');
        if($_FILES['image']['size'] <= $tailleMax)
        {
            $extensionUpload = strtolower(substr(strrchr($_FILES['image']['name'], '.'), 1));
            if(in_array($extensionUpload, $extensionsValides))
            {
                $newName =  uniqid(mt_rand(1, 5));
                $imageName = $newName.".".$extensionUpload;
                $chemin = "images/".$imageName;
                $resultat = move_uploaded_file($_FILES['image']['tmp_name'],$chemin);
            }else{
                $msg = "Le format doit être jpg, jpeg ou png";
            }
        }else{
            $msg = "Photo trop grande";
        }
    }
    if (isset($_POST['upload'])) {
        $image = $_FILES["image"]["name"];
        $about = $_POST["about"];
        $name = $_POST["name"];
        $adress = $_POST["adress"];
        $category = $_POST["category"];
        $latitude = $_POST["lat"];
        $longitude = $_POST["lng"];
        if($longitude > 48.7 and $longitude < 49 and $latitude > 2.2 and $latitude < 2.5){
            $sql = "INSERT INTO paristable 
                                (picture, name, about, adress, category, latitude, longitude) 
                        VALUES ('$imageName', '$name', '$about', '$adress', '$category', '$latitude', '$longitude')";
            mysqli_query($db, $sql);
            $msg = "Envoi réussi";
        }else{
            $smg= "Veuillez rentrer une adresse parisienne";
        }
    }else{
        $msg= "L'envoi a échoué";
    }
?>

So I added this line
if($longitude > 48.7 and $longitude < 49 and $latitude > 2.2 and $latitude < 2.5){

Because when the user post the adress I have a script which come out the latitude and longitude into hidden input. So I tried to check if he is inside Paris or not with this line. Because if the adress is not in Paris, I don't want to send the datas.
Today my form send it anyway, so i guess i have an error in this line. But i couldn't find it.
And here is my script
<script>
function showAlert(){
 var getLocation = function (address) {
    var geocoder = new google.maps.Geocoder();
    geocoder.geocode({
        'address': address
    }, function (results, status) {

        if (status == google.maps.GeocoderStatus.OK) {
            var latitude = results[0].geometry.location.lat();
            var longitude = results[0].geometry.location.lng();
            console.log(latitude, longitude);
    document.getElementById('lat').value = latitude;
            console.log(latitude);
    document.getElementById('lng').value = longitude;
            console.log(longitude);
        }
    });
};
document.getElementById('location').value = getLocation(document.getElementById('adress').value);
console.log(document.getElementById('location').value);
    document.getElementById('lat').value = latitude;
    document.getElementById('lng').value = longitude;
    console.log(document.getElementById('lat').value);
}
</script>

A:

Because when the user post the adress I have a script which come out
  the latitude and longitude into hidden input. So I tried to check if
  he is inside Paris or not with this line. Because if the adress is not
  in Paris, I don't want to send the datas.

Now that you have the user's Latlongs you can now be able to use google's geocode API to get the name of the city the coordinates are from, then if the city is Paris you can then post or else display the error Also use prepared statements to prevent against sql injections:
<?php
$msg = "";
$db  = mysqli_connect("localhost", "root", "", "dbname");
if (isset($_FILES["image"]) AND !empty($_FILES['image']['name'])) {
    $tailleMax         = 3097152;
    $extensionsValides = array(
        'jpg',
        'jpeg',
        'png'
    );
    if ($_FILES['image']['size'] <= $tailleMax) {
        $extensionUpload = strtolower(substr(strrchr($_FILES['image']['name'], '.'), 1));
        if (in_array($extensionUpload, $extensionsValides)) {
            $newName   = uniqid(mt_rand(1, 5));
            $imageName = $newName . "." . $extensionUpload;
            $chemin    = "images/" . $imageName;
            $resultat  = move_uploaded_file($_FILES['image']['tmp_name'], $chemin);
        } else {
            $msg = "Le format doit être jpg, jpeg ou png";
        }
    } else {
        $msg = "Photo trop grande";
    }
}
if (isset($_POST['upload'])) {
    $image     = $_FILES["image"]["name"];
    $about     = $_POST["about"];
    $name      = $_POST["name"];
    $adress    = $_POST["adress"];
    $category  = $_POST["category"];
    $latitude  = $_POST["lat"];
    $longitude = $_POST["lng"];

    //get geographical info of the latlongs
    $geocode = file_get_contents('http://maps.googleapis.com/maps/api/geocode/json?latlng=' . $latitude . ',' . $longitude . '&sensor=false');
    $output  = json_decode($geocode);
    for ($j = 0; $j < count($output->results[0]->address_components); $j++) {

        $city = array(
            $output->results[0]->address_components[$j]->types[0]
        );
        //get the city name
        if (in_array("locality", $city)) {
            $cityName = $output->results[0]->address_components[$j]->long_name;
        }
    }

    if ($cityName == "Paris") {
        $sql  = "INSERT INTO paristable (picture, name, about, adress, category, latitude, longitude) VALUES(?,?,?,?,?,?,?)";
        $stmt = mysqli_prepare($db, $sql);
        mysqli_stmt_bind_param($stmt, 'sssssss', $imageName, $name, $about, $adress, $category, $latitude, $longitude);

        if (mysqli_stmt_execute($stmt)) {

            $msg = "Envoi réussi";
        } else {

            $msg = mysqli_stmt_error($stmt);
        }

    } else {

        $msg = "L'envoi a échoué";
    }

} else {
    $msg = "L'envoi a échoué";
}
?>

