javascript - 更新从模式下拉列表中选择输入文本？

Question

我有一个示例模式，其中包含两个组件下拉列表和输入文本

                <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@mdo">Test Modal</button>

                <div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
                <div class="modal-dialog" role="document">
                    <div class="modal-content">
                    <div class="modal-header">
                        <h5 class="modal-title" id="exampleModalLabel">New message</h5>
                        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                        <span aria-hidden="true">&times;</span>
                        </button>
                    </div>
                    <div class="modal-body">
                        <form>
                        <div class="form-group">
                            <label for="recipient-name" class="col-form-label">Recipient:</label>
                            <select id="inputState" class="form-control">
                            <option value="john">Person 1</option>
                            <option value="adam">Person 2</option>
                            <option value="marcus">Person 3</option>
                            <option value="anthony">Person 4</option>
                            </select>
                        </div>
                        <div class="form-group">
                            <label for="message-text" class="col-form-label">Message:</label>
                            <textarea class="form-control" id="message-text"></textarea>
                        </div>
                        </form>
                    </div>
                    <div class="modal-footer">
                        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
                        <button type="button" class="btn btn-primary">Send message</button>
                    </div>
                    </div>
                </div>
                </div>

每当下拉列表更改时，我想将下拉值放入文本字​​段。 前任: 如果选择 person 2，则其值 adam 应位于文本字段中。

Answer 1

您只需监听下拉列表值的变化并将其填充到文本区域:

$( document ).ready(function(){
     $('#inputState').on('change', function(){
           $('#message-text').val($('#inputState').val())
     })
})

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@mdo">Test Modal</button>

<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
     <div class="modal-dialog" role="document">
          <div class="modal-content">
               <div class="modal-header">
                    <h5 class="modal-title" id="exampleModalLabel">New message</h5>
                    <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                         <span aria-hidden="true">&times;</span>
                    </button>
                </div>
                <div class="modal-body">
                     <form>
                          <div class="form-group">
                               <label for="recipient-name" class="col-form-label">Recipient:</label>
                               <select id="inputState" class="form-control">
                                    <option value="john">Person 1</option>
                                    <option value="adam">Person 2</option>
                                    <option value="marcus">Person 3</option>
                                    <option value="anthony">Person 4</option>
                               </select>
                          </div>
                          <div class="form-group">
                               <label for="message-text" class="col-form-label">Message:</label>
                               <textarea class="form-control" id="message-text"></textarea>
                          </div>
                     </form>
                </div>
                <div class="modal-footer">
                     <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
                     <button type="button" class="btn btn-primary">Send message</button>
                </div>
           </div>
     </div>
</div>