在Ajax和Laravel的帮助下，更新选项根据另一个select标签选择属性？

我有select标签和一系列选项选择属性，其值和内部文本存储在数据库中 .

这是我在视图上显示数据的方式，通过为每个select标记调用foreach，总共2个：

{!! Form::label('category_id', 'Category:') !!}
<select class="form-control category_id" name="category_id">
    @foreach($categories as $category)
        <option value='{{ $category->id }}'> {{ $category->name }}</option>
    @endforeach
</select>

{!! Form::label('subcategory_id', 'Subcategory:') !!}
<select class="form-control" name="subcategory_id" label="Subcategory">
    @foreach($subcategories as $subcategory)
        <option value='{{ $subcategory->id }}'> {{ $subcategory->name }}</option>
    @endforeach
</select>

问题是，我坚持以下想法：类别和子类别是一对多关系，这意味着当用户单击某个类别时，应仅使用链接到该类别的值填充选择子类别选择 .

我如何找到这个问题的解决方案，我正在考虑创建一个ajax请求，但我无法想象如何填充选项选择属性 . 或者创建一个JSON（前端的所有工作）变量来存储子类别，并根据用户选择的类别更新select标签 .

任何帮助将不胜感激 .

SOLUTION:

VIEW:

{!! Form::label('category_id', 'Category:') !!}
<select class="form-control" id="categories" name="category_id">
    @foreach($categories as $category)
        <option value='{{ $category->id }}'> {{ $category->name }}</option>
    @endforeach
</select>

<div id="displayCategories" style="display:none">
    {!! Form::label('subcategory_id', 'Subcategory:') !!}
    <select class="form-control" id="subcategories" name="subcategory_id" label="Subcategory">
        @foreach($subcategories as $subcategory)
            <option value='{{ $subcategory->id }}'> {{ $subcategory->name }}</option>
        @endforeach
    </select>
</div>

JS & JQUERY & AJAX:

<script
 src="https://code.jquery.com/jquery-3.1.1.js"
 integrity="sha256-16cdPddA6VdVInumRGo6IbivbERE8p7CQR3HzTBuELA="
 crossorigin="anonymous"></script>

<script>
$('#categories').on('change',function(e) {
    var cat_id = e.target.value;
    //ajax
    $.ajax({
        url: '../ajax-subcat/{cat_id}', //note:that the path can be different for different purpose used, in a simple page -> '/ajax-subcat/{cat_id}' so use the console of your browser
        type: 'GET',
        data: {cat_id : cat_id},
        success: function(response)
        {
            $('#subcategories').empty();
            $('#displayCategories').show();
            $.each(response, function(index, subcatObj) {
                $('#subcategories').append('<option value="' + subcatObj.id + '">' + subcatObj.name + '</option>');
                console.log(subcatObj);
            });
        }
    });
});
</script>

ROUTE:

Route::get('ajax-subcat/{cat_id}', 'PostController@getAjax');

CONTROLLER:

public function getAjax() 
{
   $cat_id = Input::get('cat_id');
   $subcategories = Subcategory::where('category_id', '=', $cat_id)->get();
   return Response::json($subcategories);
}

不要忘记在控制器中引入相应的模型，输入和响应的外观 . 就我而言：

use Illuminate\Support\Facades\Input;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Response;
use App\Category;
use App\Subcategory;