jquery - 引导模式中的滚动指示器

Question

我正在尝试计算 Bootstrap 4 模式框中的滚动指示器。

我可以正确计算窗口滚动。但是，模式框滚动内部的计算不正确。请帮助我。

$('.modal-body').scroll(function () {
  var scroll = $('.modal-body').scrollTop(),
        modalHeight = $('#exampleModalLong').height(),
        contantHeight = $('.modal-body').height();
       scrollPercent = ((scroll / (modalHeight-contantHeight)) * 100);
        var position = scrollPercent;
        var width = position+'%';

   $("#progressbar").attr('aria-valuenow', position);
   $("#progressbar").css('width', width);

   console.log('scroll is ' + scroll);
   console.log('modalHeight is ' + modalHeight);
   console.log('contantHeight is ' + contantHeight);
   console.log('width is ' + position);

});

.modal-content{
   max-height: calc(100vh - 100px);
}
.modal-body{ 
  overflow-y: auto;
}

<link rel="stylesheet" type="text/css" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script type="text/javascript" src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"></script>

<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModalLong">
  Launch demo modal
</button>

<!-- Modal -->
<div class="modal fade" id="exampleModalLong" tabindex="-1" role="dialog" aria-labelledby="exampleModalLongTitle" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLongTitle">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="progress">
				<div id="progressbar" class="progress-bar" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"></div>
			</div>
      <div class="modal-body">
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus sagittis
        lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla. Cras
        mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
          sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

当我向下滚动到底部时，我希望宽度值为 100。

Answer 1

您可以使用元素的普通 JS 属性 .scrollHeight 来获取总的可滚动高度。减去您可以使用 jQuery 函数 innerHeight() 获得的元素可见高度，您将得到总的可滚动高度。然后只需除以您编码的滚动位置即可。

$('.modal').modal();

$('.modal-body').scroll(function() {
  const scrollBox = $('.modal-body'),
    scroll = scrollBox.scrollTop(),
    scrollHeight = scrollBox[0].scrollHeight,
    containerHeight = scrollBox.innerHeight();
  scrollPercent = (scroll / (scrollHeight - containerHeight) * 100);

  $("#progressbar").attr('aria-valuenow', scrollPercent);
  $("#progressbar").css('width', scrollPercent + '%');

  console.log('scroll is ' + scroll);
  console.log('scrollPercent is ' + scrollPercent);

});

.modal-body {
  height: 150px;
  overflow-y: auto;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.bundle.min.js"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" rel="stylesheet" />


<!-- Modal -->
<div class="modal fade" id="exampleModalLong" tabindex="-1" role="dialog" aria-labelledby="exampleModalLongTitle" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLongTitle">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
      </div>
      <div class="progress">
        <div id="progressbar" class="progress-bar" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"></div>
      </div>
      <div class="modal-body">
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus sagittis
        lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla. Cras
        mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.
        Cras mattis consectetur purus sit amet fermentum. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Morbi leo risus, porta ac consectetur ac, vestibulum at eros. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Vivamus
        sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.

      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>