Seeing a lot of great but very involved answers here. There's really not a need for resetting widths, adding hidden elements, reworking elements for different layout declarations, etc. The simplest solution is just to account for the increase in size from the bold text by adjusting the font size in the hover declaration to a slightly smaller size. Like for example font-size: .985em from the normal 1em declaration, which allows the text to bold when hovered but also maintain the original size appearance.

你可以使用"margin"属性:

li a {
  margin: 0px 5px 0px 5px;
}

li a:hover {
  margin: 0;
  font-weight: bold;
}

只要确保左右边距足够大，以便额外的空间可以包含粗体文本。对于较长的单词，可以选择不同的页边距。 这只是另一种解决方法，但为我做了工作。

我固定菜单时，悬停粗体成功。它支持响应式，这是我的代码:

(function ($) {
'use strict';

$(document).ready(function () {
    customWidthMenu();
});
$(window).resize(function () {
    customWidthMenu();
});
function customWidthMenu() {
    $('ul.nav li a').each(function() {
        $(this).removeAttr('style');
        var this = $(this);
        var width = this.innerWidth();
        this.css({'width': width + 12});
    });
}})(jQuery);

我真的无法忍受有人告诉你不要那样做，而其实有一个简单的解决方法。我不确定li元素，但我刚刚修复了相同的问题。我有一个由div标签组成的菜单。

只需将div标签设置为“display: inline-block”。内联，所以他们坐在彼此和块，你可以设置宽度。只需要设置足够宽的宽度来容纳粗体文本，并使文本居中对齐。

(注意:它似乎剥离了我的html[下面]，但每个菜单项都有一个div标签围绕它与corrasponding ID和类名searchbar_category。ie: <div id="ROS_SearchSermons" class="SearchBar_Category">

超文本标记语言 (我有锚标签包装每个菜单项，但我不能提交他们作为一个新用户)

<div id="ROS_SearchSermons" class="SearchBar_Cateogry bold">Sermons</div>|
<div id="ROS_SearchIllustrations" class="SearchBar_Cateogry">Illustrations</div>|
<div id="ROS_SearchVideos" class="SearchBar_Cateogry">Videos</div>|
<div id="ROS_SearchPowerPoints" class="SearchBar_Cateogry">PowerPoints</div>|
<div id="ROS_SearchScripture" class="SearchBar_Cateogry">Scripture</div>|

CSS:

#ROS_SearchSermons { width: 75px; }
#ROS_SearchIllustrations { width: 90px; }
#ROS_SearchVideos { width: 55px; }
#ROS_SearchPowerPoints { width: 90px; }
#ROS_SearchScripture { width: 70px; }

.SearchBar_Cateogry
{
    display: inline-block;
    text-align:center;
}

通过使用一个不可见的伪元素预先设置宽度，该伪元素具有与父悬停样式相同的内容和样式。使用数据属性(如title)作为内容的源。

li { display: inline-block; font-size: 0; } li a { display:inline-block; text-align:center; font: normal 16px Arial; text-transform: uppercase; } a:hover { font-weight:bold; } /* SOLUTION */ /* The pseudo element has the same content and hover style, so it pre-sets the width of the element and visibility: hidden hides the pseudo element from actual view. */ a::before { display: block; content: attr(title); font-weight: bold; height: 0; overflow: hidden; visibility: hidden; } <ul> <li><a href="#" title="height">height</a></li> <li><a href="#" title="icon">icon</a></li> <li><a href="#" title="left">left</a></li> <li><a href="#" title="letter-spacing">letter-spacing</a></li> <li><a href="#" title="line-height">line-height</a></li> </ul>

最好使用a::before而不是a::after，就像这样:

.breadcrumb { margin: 0; padding: 0; list-style: none; overflow: hidden; } .breadcrumb li, .breadcrumb li a { display: inline-block; } .breadcrumb li:not(:last-child)::after { content: '>'; /* or anything else */ display: inline-block; } .breadcrumb a:hover { font-weight: bold; } .breadcrumb a::before { display: block; content: attr(data-label); font-weight: bold; height: 0; overflow: hidden; visibility: hidden; } <ul class="breadcrumb"> <li><a data-label="one" href="https://www.google.fr/" target="_blank">one</a></li> <li><a data-label="two" href="https://duckduckgo.com/" target="_blank">two</a></li> <li><a data-label="three" href="#">three</a></li> </ul>

详情请访问:https://jsfiddle.net/r25foavy/