如何根据“选择”框中的项目选择提供所选属性？

Question

When I select 12 or 24 or 36 in the Select box, how do I give the selected option a selected property when loaded?

 <form action="{{ route('penpal.index', ['list'=>$list,'page' => $page]) }}" method="post">
            @csrf
            <select id="inputState" class="form-control" style="height:35px; width:80%" name="list" onchange="this.form.submit()">
                <option value="12" selected>@lang('penpal/component/indexMenu.twelve')</option>
                <option value="24">@lang('penpal/component/indexMenu.twenty_four')</option>
                <option value="36">@lang('penpal/component/indexMenu.thirty_six')</option>
            </select>
        </form>

And I've chosen one more element, but I have to reload it twice, and the price of the element is applied... why?I set the default value of 12 and change the value of the list variable when the user selects the element

    if($request->list){

        $list = $request->list;
    }else{
        $list = 12;
    };

Answer 1

I dont really understand what you mean. However try this code.

<form action="{{ route('penpal.index', ['list'=>$list,'page' => $page]) }}" method="post">
            @csrf
            <select id="inputState" class="form-control" style="height:35px; width:80%" name="list" onchange="this.form.submit()">
                <option value="12" {{(old('list') == 12) ? "selected" : ""}} >@lang('penpal/component/indexMenu.twelve')</option>
                <option value="24" {{(old('list') == 24) ? "selected" : ""}} >@lang('penpal/component/indexMenu.twenty_four')</option>
                <option value="36" {{(old('list') == 36) ? "selected" : ""}} >@lang('penpal/component/indexMenu.thirty_six')</option>
            </select>
</form>

Answer 2

you have to add the HTML selected attribute

 <select id="inputState" class="form-control" style="height:35px; width:80%" name="list" onchange="this.form.submit()">
            <option value="12" selected="selected">@lang('penpal/component/indexMenu.twelve')</option>
            <option value="24">@lang('penpal/component/indexMenu.twenty_four')</option>
            <option value="36">@lang('penpal/component/indexMenu.thirty_six')</option>
        </select>