汉堡菜单不显示在响应式导航栏中

Question

你好，我是这个网络编程的新手，几天前刚学过，并尝试制作我的响应式导航栏。我在 w3school 上找到了教程，我遵循了它，并更改了一些代码，但它没有按预期工作。菜单成功折叠在所需宽度上，但汉堡菜单未显示。我想我已经改变了它并与我的课程相匹配，但我不知道还有什么问题。

这是我到目前为止尝试过的：

.navSection {
width: 100%;
display: inline-table;
line-height: 30px;
background: #1c948a;
z-index: 3;
box-shadow: 0px 3px 5px 1px rgba(0, 0, 0, .3);
}
.navMenu .icon{
display: none;
}
@media screen and (max-width: 700px) {
.navMenu ul li:not(:first-child) {display: none;}
.navMenu ul li.icon {
float: right;
display: block;
}
}
@media screen and (max-width: 700px) {
.navMenu.responsive {position: relative;}
.navMenu.responsive .icon {
position: absolute;
right: 0;
top: 0;
}
.navMenu.responsive ul li {
float: none;
display: block;
text-align: left;
}
}
.navSectionWrapper {
width: 90%;
margin: auto;
}
.homelink {
text-decoration: none;
}
.navlogo {
width: 30%;
height: 70px;
float: left;
}
.logo {
display: inline-block;
font-family: "Trebuchet MS", "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", Tahoma, sans-serif;
color: #2C3E50;
position: absolute;
}
.logoimg {
height: 70px;
float: left;
}
.logotext {
font-weight: 600;
float: right;
line-height: 70px;
}
.logotext>span {
color: white;
text-shadow: 2px 2px 2px #33425B;
}
.navMenu {
float: right;
text-align: center;
overflow: hidden;
}
.navMenu>ul {
list-style: none;
}
.navMenu>ul>li {
display: inline-block;
line-height: 70px;
}
.navMenu>ul>li>a>span {
color: white;
font-weight: 700;
font-size: 17px
}
.navMenu>ul>li>a {
text-decoration: none;
color: #2C3E50;
font-family: "Trebuchet MS", "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", Tahoma, sans-serif;
font-weight: 600;
margin: 10px
}
.navMenu>ul>li>a:hover {
color: snow;
}

<div class="navSection">
<div class="navSectionWrapper">
<div class="navlogo">
<a href="#" class="homelink">
<div class="logo">
<img src="img/logo.png" class="logoimg">
<h2 class="logotext">Let's<span>Go</span></h2>
</div>
</a>
</div>
<div class="navMenu" id="mynavMenu">
<ul>
<li><a href="#">Home</a></li>
<li><a href="#">Features</a></li>
<li><a href="#">About</a></li>
<li><a href="#">+<span>Download</span></a></li>
<li><a href="javascript:void(0);" class="icon" onclick="myFunction()">&#9776;</a></li>
</ul>
</div>
</div>
</div>
<script>
function myFunction() {
var x = document.getElementById("mynavMenu");
if (x.className === "navMenu") {
x.className += " responsive";
} else {
x.className = "navMenu";
}
}
</script>

谢谢

Answer 1

您的 HTML 使用a.icon但您在 CSS 中定位时li.icon.将class="icon"移动到li而不是a，并稍微修改了.iconCSS。您在响应式视图中隐藏了:not(:first-child())，并且您要么想使用:not(:last-child)，因为.icon是:last-child，要么只是在那里使用:not(.icon)。

.navSection {
width: 100%;
display: inline-table;
line-height: 30px;
background: #1c948a;
z-index: 3;
box-shadow: 0px 3px 5px 1px rgba(0, 0, 0, .3);
}
.navMenu .icon{
display: none;
float: right;
}
@media screen and (max-width: 700px) {
.navMenu ul li:not(.icon) {display: none;}
.navMenu ul li.icon {
display: block;
}
}
@media screen and (max-width: 700px) {
.navMenu.responsive {position: relative;}
.navMenu.responsive .icon {
position: absolute;
right: 0;
top: 0;
}
.navMenu.responsive ul li {
float: none;
display: block;
text-align: left;
}
}
.navSectionWrapper {
width: 90%;
margin: auto;
}
.homelink {
text-decoration: none;
}
.navlogo {
width: 30%;
height: 70px;
float: left;
}
.logo {
display: inline-block;
font-family: "Trebuchet MS", "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", Tahoma, sans-serif;
color: #2C3E50;
position: absolute;
}
.logoimg {
height: 70px;
float: left;
}
.logotext {
font-weight: 600;
float: right;
line-height: 70px;
}
.logotext>span {
color: white;
text-shadow: 2px 2px 2px #33425B;
}
.navMenu {
float: right;
text-align: center;
overflow: hidden;
}
.navMenu>ul {
list-style: none;
}
.navMenu>ul>li {
display: inline-block;
line-height: 70px;
}
.navMenu>ul>li>a>span {
color: white;
font-weight: 700;
font-size: 17px
}
.navMenu>ul>li>a {
text-decoration: none;
color: #2C3E50;
font-family: "Trebuchet MS", "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", Tahoma, sans-serif;
font-weight: 600;
margin: 10px
}
.navMenu>ul>li>a:hover {
color: snow;
}

<div class="navSection">
<div class="navSectionWrapper">
<div class="navlogo">
<a href="#" class="homelink">
<div class="logo">
<img src="img/logo.png" class="logoimg">
<h2 class="logotext">Let's<span>Go</span></h2>
</div>
</a>
</div>
<div class="navMenu" id="mynavMenu">
<ul>
<li><a href="#">Home</a></li>
<li><a href="#">Features</a></li>
<li><a href="#">About</a></li>
<li><a href="#">+<span>Download</span></a></li>
<li class="icon"><a href="javascript:void(0);" onclick="myFunction()">&#9776;</a></li>
</ul>
</div>
</div>
</div>
<script>
function myFunction() {
var x = document.getElementById("mynavMenu");
if (x.className === "navMenu") {
x.className += " responsive";
} else {
x.className = "navMenu";
}
}
</script>