当我想改变一个特定弹出窗口的宽度时，我发现了这个Bootstrap 5+的解决方案。添加customClass对我有用:

Html:

<button class="btn btn-outline-secondary"  id="popover-help" data-bs-container="body" data-bs-toggle="popover" data-bs-placement="right" data-bs-content="Right popover">
   <i class="fa fa-question-circle"></i>
</button>

<div id="popover-help-container" style="display: none;">
    <h4 style="text-align: left;"> How to:</h4>
    <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec condimentum ultricies elit, mattis egestas nisl suscipit ac. Duis ipsum augue, convallis sed nunc in, pellentesque luctus elit. Duis porttitor massa sed finibus rutrum. Nunc eu risus ultrices, volutpat leo eget, pulvinar eros. Donec rhoncus mattis sem, ac iaculis turpis semper non. Cras dapibus tristique risus, eu tincidunt elit condimentum fermentum. Nunc at dignissim ante, nec efficitur felis. Duis mauris magna, fermentum eu egestas vel, vehicula at est. Nullam dapibus nisi non purus pellentesque ultrices. Nulla pulvinar neque quis ipsum semper, a congue tortor aliquet. Suspendisse vulputate porttitor feugiat. Maecenas pretium porta mauris feugiat pellentesque. Integer tempus risus eu pretium consectetur.

Donec interdum, eros ac imperdiet pretium, magna risus laoreet tellus, in finibus justo sapien et lacus. Pellentesque placerat ligula at metus sollicitudin, et convallis nisi luctus. Vivamus non arcu vel ex pharetra auctor. Morbi efficitur sed turpis id finibus. Sed porttitor luctus quam sed laoreet. Nunc facilisis finibus aliquet. Maecenas pellentesque sem dui, sed blandit tortor placerat ut. Donec tempor ipsum in sem fermentum, vel vulputate magna egestas.</p>
</div> 

JS:

<script type="text/javascript">
    var popoverTriggerList = [].slice.call(document.querySelectorAll('[id="popover-help"]'))
    var popoverList = popoverTriggerList.map(function (popoverTriggerEl) {
    return new bootstrap.Popover(popoverTriggerEl,{
        content: function() {
                return $('#popover-help-container').html();
            },
        html: true,
        placement: 'bottom',
        sanitize: false,
        customClass: 'popover-large'
        });
    })
</script>

css:

.popover-large {
  max-width: 50%; /* Max Width of the popover (depending on the container!) */
}

要改变宽度，你可以使用css

需要固定尺寸

.popover{
    width:200px;
    height:250px;    
}

需要的最大宽度:

.popover{
    max-width:200px;
    height:250px;    
}

jsfiddle: http://jsfiddle.net/Rqx8T/2/

对于喜欢JavaScript解决方案的人。 在Bootstrap 4中tip()变成了getTipElement()，它返回一个非jQuery对象。所以为了改变弹出窗口的宽度在Bootstrap 4你可以使用:

}).on("show.bs.popover", function() {
    $($(this).data("bs.popover").getTipElement()).css("max-width", "405px");
});

在Angular ng-bootstrap中，你可以简单地将container="body"添加到触发弹窗(比如按钮或文本框)的控件中。然后在你的全局样式文件(style.css或style.scss)文件中，你必须添加.popover {max-width: 100% !}。之后，弹出窗口的内容将自动设置为其内容宽度。

<div class="row" data-toggle="popover" data-trigger="hover" 
                 data-content="My popover content.My popover content.My popover content.My popover content.">
<div class="col-md-6">
    <label for="name">Name:</label>
    <input id="name" class="form-control" type="text" />
</div>
</div>

基本上我把弹窗代码放在行div，而不是输入div。解决了这个问题。

下面是使用hover的非coffeescript方式:

$(".product-search-trigger").popover({
    trigger: "hover",
    container: "body",
    html: true,
    placement: "left"
  }).on("show.bs.popover", function() {
    return $(this).data("bs.popover").tip().css({
      maxWidth: "300px"
    });
  });
});