Laravel 5.5 -> Dynamically updating second dropdown, based on first dropdown.

@extends('layouts/main')

@section('content')
<div class="container">
    <div class="row justify-content-center">
        <div class="col-md-8">
            <div class="card card-default">
                <div class="card-header">Advertise Your Ad</div>

                <div class="card-body">
                    <form method="POST" action="/createadvert">
                        @csrf

                        <!-- Address -->
                        <div class="form-group row">
                            <label for="address" class="col-md-3 col-form-label text-md-right">Address</label>
                            <div class="col-md-9">
                                <input id="Address" type="text" class="form-control{{ $errors->has('Address') ? ' is-invalid' : '' }}" name="address" value="{{ old('Address') }}" required autofocus>
                                @if ($errors->has('Address'))
                                    <span class="invalid-feedback">
                                        <strong>{{ $errors->first('Address') }}</strong>
                                    </span>
                                @endif
                            </div>
                        </div>

                        <!-- County -->
                        <div class="form-group row">
                          <label for="county" class="col-md-3 col-form-label text-md-right">County</label>
                            <div class="col-md-9">
                              <select class ="form-control" id="county" name="county">
                                <option>Dublin</option>
                                <option>Galway</option>
                              </select>
                              @if ($errors->has('county'))
                                  <span class="invalid-feedback">
                                      <strong>{{ $errors->first('county') }}</strong>
                                  </span>
                              @endif
                            </div>
                        </div>


                        <!-- city -->
                        <div class="form-group row">
                          <label for="city" class="col-md-3 col-form-label text-md-right">city</label>
                            <div class="col-md-9">
                              <select class ="form-control" id="city" name="city">
                                <option>Howth</option>
                                <option>Sutton</option>
                              </select>
                              @if ($errors->has('city'))
                                  <span class="invalid-feedback">
                                      <strong>{{ $errors->first('city') }}</strong>
                                  </span>
                              @endif
                            </div>
                        </div>



                        <div class="form-group row mb-0">
                            <div class="col-md-6 offset-md-4">
                                <button type="submit" class="btn btn-primary">
                                    Submit
                                </button>
                            </div>
                        </div>
                    </form>
                </div>
            </div>
        </div>
    </div>
</div>
@endsection

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\PropertyAdvert;

class AdvertisementController extends Controller
{
    public function index(){
      return view('pages/Advert/create');
    }

    public function store(Request $request){
      $Advert = new PropertyAdvert();

      $Advert::create(
        [
          "address" => $request->address,
          "county" => $request->county,
          "town" => $request->town,

        ]
      );

      return "Success. Your adveret has been published";
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class PropertyAdvert extends Model
{
     protected $fillable = ["address", "county", "town",];
}

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreatePropertyAdvertsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('property_adverts', function (Blueprint $table) {
            $table->increments('id');
            $table->string('address');
$table->string('county');
            $table->string('town');
            $table->string('type');
 
        });
    }

    
}