点击按钮时Bootstrap Modal无法弹出问题求助

你的问题出在重复引入了Bootstrap的JS文件：你同时加载了bootstrap.min.js和bootstrap.bundle.min.js，这两个文件功能重叠，会导致JavaScript冲突，进而让Modal的触发逻辑失效。

Bootstrap 4的bootstrap.bundle.min.js已经包含了Popper.js和必要的jQuery功能，不需要再单独引入bootstrap.min.js、jQuery和Popper.js；或者你可以选择只引入bootstrap.min.js，同时搭配jQuery和Popper.js，但不能两种方式混用。

修复后的代码示例（二选一即可） #

方案一：使用bundle版本（推荐） #

<link href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css" rel="stylesheet" />

<button class="btn btn-success btn-lg" data-toggle="modal" data-target="#signUpModal">Sign Up!</button>

<div class="modal" tabindex="-1" id="signUpModal">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">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">
        <p>Modal body text goes here.</p>
      </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>
<!-- 只保留bundle版本即可 -->
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-Fy6S3B9q64WdZWQUiU+q4/2Lc9npb8tCaSX9FK7E8HnRr0Jz8D6OP9dO5Vg3Q9ct" crossorigin="anonymous">
</script>

方案二：使用单独的JS文件 #

<link href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css" rel="stylesheet" />

<button class="btn btn-success btn-lg" data-toggle="modal" data-target="#signUpModal">Sign Up!</button>

<div class="modal" tabindex="-1" id="signUpModal">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">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">
        <p>Modal body text goes here.</p>
      </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>
<!-- 移除bootstrap.bundle.min.js，保留单独的依赖和bootstrap.min.js -->
<script src="https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/js/bootstrap.min.js" integrity="sha384-+sLIOodYLS7CIrQpBjl+C7nPvqq+FbNUBDunl/OZv93DB7Ln/533i8e/mZXLi/P+" crossorigin="anonymous"></script>

内容的提问来源于stack exchange，提问作者Sizmon