你可以使用jQuery来处理这个问题

首先在模板上导入

<script src="https://code.jquery.com/jquery-3.6.0.min.js" integrity="sha256-/xUj+3OJU5yExlq6GSYGSHk7tPXikynS7ogEvDej/m4=" crossorigin="anonymous"></script>

然后用jQuery脚本在你的模式上点击id

<script type="text/javascript">
      $(window).on('load', function() {
        $('#staticBackdrop').modal('show');
    });
</script>

这里是modal用于case显示的django消息

{% if messages %}
      {% for message in messages %}
      <div class="modal fade" id="staticBackdrop" data-bs-backdrop="static" data-bs-keyboard="false" tabindex="-1" aria-labelledby="staticBackdropLabel" aria-hidden="false">
        <div class="modal-dialog">
          <div class="modal-content">
            <div class="modal-header">
              <h5 class="modal-title" id="staticBackdropLabel">Message</h5>
              <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
            </div>
            <div class="modal-body">
              {{ message }}
            </div>
            <div class="modal-footer">
              <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
            </div>
          </div>
        </div>
      </div>
      {% endfor %}
        
    {% endif %}

更新2020 -引导5

建立在优秀的回应从以前的答案，在Bootstrap 5没有jQuery，这已经工作;

document.querySelector('[data-target="#exampleModal"]').click();

完整的片段:

window.onload = () => { document.querySelector('[data-target="#exampleModal"]').click(); } <script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/js/bootstrap.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js"></script> <link href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/css/bootstrap.min.css" rel="stylesheet" /> <div class="container py-3"> <!-- Button trigger modal --> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal"> Launch demo modal </button> <!-- Modal --> <div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true"> <div class="modal-dialog"> <div class="modal-content"> <div class="modal-header"> <h5 class="modal-title" id="exampleModalLabel">Modal title</h5> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">&times;</span> </button> </div> <div class="modal-body"> ... </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> </div>

你可能想要保持jquery.js延迟，以更快的页面加载。但是，如果jquery.js被延迟到$(window)。负载可能不工作。那么你可以试试

setTimeout（function（）{$（'#myModal'）.modal（'show'）;}，3000）;

它会在页面完全加载后弹出你的模态(包括jquery)

你不需要javascript来显示模态

最简单的方法是将"hide"替换为"in"

class="modal fade hide"

so

class="modal fade in"

你需要添加onclick = "$('.modal').hide()"按钮关闭;

PS:我认为最好的方法是添加jQuery脚本:

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

只需添加下面的-

class="modal show"

工作示例,

<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script> <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> <div class="container"> <!-- Trigger the modal with a button --> <button type="button" class="btn btn-info btn-lg" data-toggle="modal" data-target="#myModal">Open Modal</button> <!-- Modal --> <div class="modal show" id="myModal" role="dialog"> <div class="modal-dialog"> <!-- Modal content--> <div class="modal-content"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal">&times;</button> <h4 class="modal-title">Modal Header</h4> </div> <div class="modal-body"> <p>Some text in the modal.</p> </div> <div class="modal-footer"> <button type="button" class="btn btn-default" data-dismiss="modal">Close</button> </div> </div> </div> </div> </div>

就像其他人提到的，用display:block创建你的模态

<div class="modal in" tabindex="-1" role="dialog" style="display:block">
...

将背景放置在页面的任何地方，它不一定要在页面的底部

<div class="modal-backdrop fade show"></div> 

然后，为了能够再次关闭对话框，添加这个

<script>
    $("button[data-dismiss=modal]").click(function () {
        $(".modal.in").removeClass("in").addClass("fade").hide();
        $(".modal-backdrop").remove();
    });
</script>

希望这能有所帮助