Question

我试图根据w3schools的example来实现CSS下拉菜单。它正常工作，但dropbtn类的左边距与简单导航链接（Home，News）的左边距不同。当您从一个列表项移动到另一个列表项时，实现下拉菜单的项目左侧有一个黑色边框，我无法解释。

当我尝试使用li + li在项目之间实现分隔符时，会出现此行为：之前显示为here。

default.html中

<!DOCTYPE HTML>
<html>
<head>
    <link rel="stylesheet" type="text/css" href="styles/style.css" />
</head>
<body>
    <ul>
        <li><a href="#home">Home</a></li>
        <li><a href="#news">News</a></li>
        <li class="dropdown">
            <a href="javascript:void(0)" class="dropbtn">Dropdown</a>
            <div class="dropdown-content">
                <a href="#">Link 1</a>
                <a href="#">Link 2</a>
                <a href="#">Link 3</a>
            </div>
        </li>
    </ul>
    <h3>Dropdown Menu inside a Navigation Bar</h3>
    <p>Hover over the "Dropdown" link to see the dropdown menu.</p>
</body>
</html>

的style.css

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
}

li {
    float: left;
}

li+li:before {
    color: white;
    content: "|";
}

li a, .dropbtn {
    display: inline-block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

li a:hover, .dropdown:hover .dropbtn {
    background-color: red;
}

li.dropdown {
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    text-align: left;
}

.dropdown-content a:hover {background-color: #f1f1f1}

.dropdown:hover .dropdown-content {
    display: block;
}

Answer 1

您可以更准确地定位before元素：

li {
    float: left;
    position: relative;
}

li+li:before {
    color: white;
    content: "|";
    left: -1px;
    top: 14px;
    position: absolute;
}

https://jsfiddle.net/oao3yt8w/

CSS相邻兄弟打破下拉菜单边距

1 个答案: