<script type="text/javascript">
$(document).ready(function(){
    $('#country').on('change',function(){
        var countryID = $(this).val();
        if(countryID){
            $.ajax({
                type:'POST',
                url:'ajaxData.php',
                data:'country_id='+countryID,
                success:function(html){
                    $('#state').html(html);
                    $('#city').html('<option value="">Select state first</option>');
                }
            });
        }else{
            $('#state').html('<option value="">Select country first</option>');
            $('#city').html('<option value="">Select state first</option>');
        }
    });

    $('#state').on('change',function(){
        var stateID = $(this).val();
        if(stateID){
            $.ajax({
                type:'POST',
                url:'ajaxData.php',
                data:'state_id='+stateID,
                success:function(html){
                    $('#city').html(html);
                }
            });
        }else{
            $('#city').html('<option value="">Select state first</option>');
        }
    });
});
</script>


  <?php
    //Include database configuration file
    include('dbConfig.php');

    //Get all country data
    $query = $db->query("SELECT * FROM countries WHERE status = 1 ORDER BY country_name ASC");

    //Count total number of rows
    $rowCount = $query->num_rows;
    ?>
    <select name="country" id="country" >
        <option value="">Select Country</option>
        <?php
        if($rowCount > 0){
            while($row = $query->fetch_assoc()){
                echo '<option value="'.$row['country_id'].'">'.$row['country_name'].'</option>';
            }
        }else{
            echo '<option value="">Country not available</option>';
        }
        ?>
    </select>

    <select name="state" id="state">
        <option value="">Select country first</option>
    </select>

    <select name="city" id="city">
        <option value="">Select state first</option>
    </select>

<?php
//Include database configuration file
include('dbConfig.php');

if(isset($_POST["country_id"]) && !empty($_POST["country_id"])){
    //Get all state data
    $query = $db->query("SELECT * FROM states WHERE country_id = ".$_POST['country_id']." AND status = 1 ORDER BY state_name ASC");

    //Count total number of rows
    $rowCount = $query->num_rows;

    //Display states list
    if($rowCount > 0){
        echo '<option value="">Select state</option>';
        while($row = $query->fetch_assoc()){
            echo '<option value="'.$row['state_id'].'">'.$row['state_name'].'</option>';
        }
    }else{
        echo '<option value="">State not available</option>';
    }
}

if(isset($_POST["state_id"]) && !empty($_POST["state_id"])){
    //Get all city data
    $query = $db->query("SELECT * FROM cities WHERE state_id = ".$_POST['state_id']." AND status = 1 ORDER BY city_name ASC");

    //Count total number of rows
    $rowCount = $query->num_rows;

    //Display cities list
    if($rowCount > 0){
        echo '<option value="">Select city</option>';
        while($row = $query->fetch_assoc()){
            echo '<option value="'.$row['city_id'].'">'.$row['city_name'].'</option>';
        }
    }else{
        echo '<option value="">City not available</option>';
    }
}
?>

<?php
//db details
$dbHost = 'localhost';
$dbUsername = 'root';
$dbPassword = '';
$dbName = 'lisenme';

//Connect and select the database
$db = new mysqli($dbHost, $dbUsername, $dbPassword, $dbName);

if ($db->connect_error) {
    die("Connection failed: " . $db->connect_error);
}
?>