Bootstrap4 导航栏
导航栏一般放在页面的顶部。
我们可以使用
.navbar
类来创建一个标准的导航栏,后面紧跟:
.navbar-expand-xl|lg|md|sm
类来创建响应式的导航栏
(大屏幕水平铺开,小屏幕垂直堆叠)。
导航栏上的选项可以使用
<ul>
元素并添加
class="navbar-nav"
类。
然后在
<li>
元素上添加
.nav-item
类,
<a>
元素上使用
.nav-link
类:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-light
"
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 1
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 2
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 3
</
a
>
</
li
>
</
ul
>
</
nav
>
尝试一下 »
垂直导航栏
通过删除
.navbar-expand-xl|lg|md|sm
类来创建垂直导航栏:
实例
<
nav
class
=
"
navbar bg-light
"
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 1
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 2
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 3
</
a
>
</
li
>
</
ul
>
</
nav
>
尝试一下 »
居中对齐的导航栏
通过添加
.justify-content-center
类来创建居中对齐的导航栏:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-light justify-content-center
"
>
...
</
nav
>
尝试一下 »
不同颜色导航栏
可以使用以下类来创建不同颜色导航栏:
.bg-primary
,
.bg-success
,
.bg-info
,
.bg-warning
,
.bg-danger
,
.bg-secondary
,
.bg-dark
和
.bg-light
)。
提示:
对于暗色背景需要设置文本颜色为浅色的,对于浅色背景需要设置文本颜色为深色的。
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-light navbar-light
"
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item active
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Active
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link disabled
"
href
=
"
#
"
>
Disabled
</
a
>
</
li
>
</
ul
>
</
nav
>
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
...
</
nav
>
<
nav
class
=
"
navbar navbar-expand-sm bg-primary navbar-dark
"
>
...
</
nav
>
尝试一下 »
激活和禁用状态
: 可以在
<a>
元素上添加
.active
类来高亮显示选中的选项。
.disabled
类用于设置该链接是不可点击的。
品牌/Logo
.navbar-brand
类用于高亮显示品牌/Logo:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
a
class
=
"
navbar-brand
"
href
=
"
#
"
>
Logo
</
a
>
...
</
nav
>
尝试一下 »
可以使用
.navbar-brand
类来设置图片自适应导航栏。
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
a
class
=
"
navbar-brand
"
href
=
"
#
"
>
<
img
src
=
"
bird.jpg
"
alt
=
"
Logo
"
style
=
"
width:40px;
"
>
</
a
>
...
</
nav
>
尝试一下 »
折叠导航栏
通常,小屏幕上我们都会折叠导航栏,通过点击来显示导航选项。
要创建折叠导航栏,可以在按钮上添加
class="navbar-toggler",
data-toggle="collapse" 与 data-target="#thetarget"
类。然后在设置了
class="collapse navbar-collapse"
类的 div 上包裹导航内容(链接), div 元素上的 id 匹配按钮
data-target
的上指定的 id:
实例
<
nav
class
=
"
navbar navbar-expand-md bg-dark navbar-dark
"
>
<
a
class
=
"
navbar-brand
"
href
=
"
#
"
>
Navbar
</
a
>
<
button
class
=
"
navbar-toggler
"
type
=
"
button
"
data-toggle
=
"
collapse
"
data-target
=
"
#collapsibleNavbar
"
>
<
span
class
=
"
navbar-toggler-icon
"
>
</
span
>
</
button
>
<
div
class
=
"
collapse navbar-collapse
"
id
=
"
collapsibleNavbar
"
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link
</
a
>
</
li
>
</
ul
>
</
div
>
</
nav
>
尝试一下 »
导航栏使用下拉菜单
导航栏上可以设置下拉菜单:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
a
class
=
"
navbar-brand
"
href
=
"
#
"
>
Logo
</
a
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 1
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 2
</
a
>
</
li
>
<
li
class
=
"
nav-item dropdown
"
>
<
a
class
=
"
nav-link dropdown-toggle
"
href
=
"
#
"
id
=
"
navbardrop
"
data-toggle
=
"
dropdown
"
>
Dropdown link
</
a
>
<
div
class
=
"
dropdown-menu
"
>
<
a
class
=
"
dropdown-item
"
href
=
"
#
"
>
Link 1
</
a
>
<
a
class
=
"
dropdown-item
"
href
=
"
#
"
>
Link 2
</
a
>
<
a
class
=
"
dropdown-item
"
href
=
"
#
"
>
Link 3
</
a
>
</
div
>
</
li
>
</
ul
>
</
nav
>
尝试一下 »
导航栏的表单与按钮
导航栏的表单
<form>
元素使用
class="form-inline"
类来排版输入框与按钮:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
form
class
=
"
form-inline
"
>
<
input
class
=
"
form-control
"
type
=
"
text
"
placeholder
=
"
Search
"
>
<
button
class
=
"
btn btn-success
"
type
=
"
submit
"
>
Search
</
button
>
</
form
>
</
nav
>
尝试一下 »
你也可以使用其他的输入框类,如
.input-group-addon
类用于在输入框前添加小标签。
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
form
class
=
"
form-inline
"
action
=
"
/action_page.php
"
>
<
div
class
=
"
input-group
"
>
<
div
class
=
"
input-group-prepend
"
>
<
span
class
=
"
input-group-text
"
>
@
</
span
>
</
div
>
<
input
type
=
"
text
"
class
=
"
form-control
"
placeholder
=
"
Username
"
>
</
div
>
</
form
>
</
nav
>
尝试一下 »
导航栏文本
使用
.navbar-text
类来设置导航栏上非链接文本,可以保证水平对齐,颜色与内边距一样。
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark
"
>
<
ul
class
=
"
navbar-nav
"
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 1
</
a
>
</
li
>
<
li
class
=
"
nav-item
"
>
<
a
class
=
"
nav-link
"
href
=
"
#
"
>
Link 2
</
a
>
</
li
>
</
ul
>
<
span
class
=
"
navbar-text
"
>
Navbar text
</
span
>
</
nav
>
尝试一下 »
固定导航栏
导航栏可以固定在头部或者底部。
我们使用
.fixed-top
类来实现导航栏的固定:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark fixed-top
"
>
...
</
nav
>
尝试一下 »
.fixed-bottom
类用于设置导航栏固定在底部:
实例
<
nav
class
=
"
navbar navbar-expand-sm bg-dark navbar-dark fixed-bottom
"
>
...
</
nav
>
尝试一下 »