How to get City dropdown list after selecting State in PHP-CodePudding

Firstly I want to select State from the dropdown list and then based on the state that I selected, I want to display the cities in that state. How should I do that?

This is in addCat.php

   <?php
                                $selectStates = $categoryObject->selectStates();
                                $selectCities = $categoryObject->selectCities($selectStates);
                            ?>
                            <div class="x_content">
                                <br />
                                <form id="demo-form2" data-parsley-validate class="form-horizontal form-label-left" action="" method="POST">
    
                                    <div class="form-group">
                                        <label class="control-label col-md-3 col-sm-3 col-xs-12" for="first-name">State Name <span class="required">*</span>
                                        </label>
                                        <div class="col-md-6 col-sm-6 col-xs-12">
                                            <select  id="first-name" required="required" name="category" class="form-control col-md-7 col-xs-12">
                                            <option value="">--Select--</option>
                                            <?php
                                            while($res = $selectStates->fetch_assoc())
                                            {
                                            ?>
                                            <option value="<?php echo $res["state_id"]; ?>"><?php echo $res["state_title"]; ?></option>
                                            <?php
                                            }
                                            ?>
                                            </select>
                                        </div>
                                    </div>
                                    <div class="form-group">
                                        <label class="control-label col-md-3 col-sm-3 col-xs-12" for="first-name">City Name <span class="required">*</span>
                                        </label>
                                        <div class="col-md-6 col-sm-6 col-xs-12">
                                            <select id="first-name" required="required" name="category" class="form-control col-md-7 col-xs-12">
                                            <option value="">--Select--</option>
                                            <?php
                                            while($res = $selectCities->fetch_assoc())
                                            {
                                            ?>
                                            <option value="<?php echo $res["state_id"]; ?>"><?php echo $res["name"]; ?></option>
                                            <?php
                                            }
                                            ?>
                                            </select>
                                        </div>
                                    </div>
                                    <div class="ln_solid"></div>
                                    <div class="form-group">
                                        <div class="col-md-6 col-sm-6 col-xs-12 col-md-offset-3">
                                            <button type="submit" class="btn btn-app" name="addCategory"><i class="fa fa-save"></i> Save</button>
                                            <button class="btn btn-app" type="reset"><i class="fa fa-repeat"></i> Reset</button>
                                        </div>
                                    </div>
    
                                </form>
                            </div>

This is in category.php

public function selectStates()
        {
            $states = "SELECT * FROM states";
            return $this->db->select($states);
        }
        
        
        public function selectCities($states)
        {
            $cities = "SELECT * FROM city ORDER BY name ASC";
            return $this->db->select($cities);
        }

There are two tables cities and states. Cities have 'name' and 'state_id', while states have 'state_title' and 'state_id'

I am stuck on how to connect category.php and addCat.php as well as what code should I write as JS? I tried to find it on my own, But I am unable to use anything on my code. If someone can write that code for me, It would be really helpful. Please don't downvote the question. Not everyone is a pro-coder.

CodePudding user response：

You can with JS ajax onchange Example: https://www.tutsmake.com/country-state-city-database-in-mysql-php-ajax/