在bootstrap 3中，你只需要通过js初始化模态，如果在页面加载的时刻，模态标记在页面中，模态就会显示出来。

如果你想防止这种情况，可以在初始化模态的地方使用show: false选项。就像这样: $ (' .modal ')。Modal ({show: false})

您可以通过数据属性激活模态，而不需要编写任何JavaScript。

选项"show"设为true显示初始化时的模态:

<div class="modal fade" tabindex="-1" role="dialog" data-show="true"></div>

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>

更新2021

引导5

现在Bootstrap不再需要jQuery，使用JavaScript显示模态很容易。

var myModal = new bootstrap.Modal(document.getElementById('myModal'), {})
myModal.toggle()

Demo

引导4

Bootstrap 4的模式标记略有变化。下面是如何在页面加载时打开模态，并可选地延迟显示模态…

$(window).on('load',function(){
    var delayMs = 1500; // delay in milliseconds
    
    setTimeout(function(){
        $('#myModal').modal('show');
    }, delayMs);
});    

<div class="modal fade" id="myModal">
      <div class="modal-dialog modal-lg modal-dialog-centered" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <h4 class="modal-title">My Modal</h4>
                    <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                        <span aria-hidden="true">×</span>
                    </button>
                </div>
                <div class="modal-body">
                    ...
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-secondary mx-auto" data-dismiss="modal">Close</button>
                </div>
            </div>
      </div>
</div>

Demo

除了user2545728和Reft的答案，没有javascript，但与情态背景

添加3件事

一个在.modal类之前带有modal- background类的div Style ="display:block;"到.modal类 与.modal类一起淡出

例子

<div class="modal-backdrop in"></div>

<div class="modal fade in" tabindex="-1" role="dialog" aria-labelledby="channelModal" style="display:block;">

    <div class="modal-dialog modal-lg" role="document">

        <div class="modal-content">

            <div class="modal-header">

                <h4 class="modal-title" id="channelModal">Welcome!</h4>

            </div>

            <div class="modal-body" style="height:350px;">

                How did you find us?

            </div>

        </div>

    </div>

</div>

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');