打开fancybox窗口时从表单字段中删除自动对焦？

$('[data-fancybox]').fancybox({
  touch: false,
  afterShow: function(instance, current) {
    $(".form-control").attr('tabindex', '-1');
    $(".form-control").attr('autofocus', 'false');

  },
  beforeShow: function(instance, current) {
    $(".form-control").attr('tabindex', '-1');
    $(".form-control").attr('autofocus', 'false');
  }
});

.fancy-modal {
  display: none;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/fancybox/3.5.7/jquery.fancybox.min.css" integrity="sha256-Vzbj7sDDS/woiFS3uNKo8eIuni59rjyNGtXfstRzStA=" crossorigin="anonymous" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/fancybox/3.5.7/jquery.fancybox.min.js" integrity="sha256-yt2kYMy0w8AbtF89WXb2P1rfjcP/HTHLT7097U8Y5b8=" crossorigin="anonymous"></script>

<a data-fancybox data-src="#cb" href="javascript:;" class="btn btn-success">open</a>

<div id="cb" class="fancy-modal">
  <form>
    <div class="form-group">
      <label for="exampleInputEmail1">Email address</label>
      <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp">
      <small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small>
    </div>
    <div class="form-group">
      <label for="exampleInputPassword1">Password</label>
      <input type="password" class="form-control" id="exampleInputPassword1">
    </div>
    <div class="form-group form-check">
      <input type="checkbox" class="form-check-input" id="exampleCheck1">
      <label class="form-check-label" for="exampleCheck1">Check me out</label>
    </div>
    <button type="submit" class="btn btn-primary">Submit</button>
  </form>
</div>