0
0
mirror of https://github.com/twbs/bootstrap.git synced 2025-01-09 02:46:15 +01:00
Bootstrap/site/content/docs/4.6/components/navbar.md
Patrick H. Lauke f4a1a35cf2
v4: Disabled link cleanup (#34924)
manual backport of #34886

per https://www.w3.org/TR/html-aria/#docconformance

> It is NOT RECOMMENDED to use `aria-disabled="true"` on an `a` element with an `href` attribute.
>
>NOTE
>If a link needs to be "disabled", remove the `href` attribute.

This PR removes the unnecessary `href="#"`, `tabindex="-1"`, and `aria-disabled="true"` from disabled links in both docs pages and examples. `aria-disabled="true"` *is* kept for disabled link-based buttons (that have `role="button"`) as there it's appropriate to use (you *want* to convey to assistive technologies that this thing you're claiming is a button is also disabled at the moment)

Further, the PR extends the "Link functionality caveat" to show the "proper" way (removing `href` and adding `.disabled` class only) to disable a link, but then explains what to do if that's not possible (and then keeps an example with all the traditional `href="#" tabindex="-1" aria-disabled="true"`, but explains clearly that it's not ideal). Same sort of explanation is also added to the pointer event utilities page
2021-09-09 14:49:06 +03:00

603 lines
26 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
layout: docs
title: Navbar
description: Documentation and examples for Bootstrap's powerful, responsive navigation header, the navbar. Includes support for branding, navigation, collapse plugin, and more.
group: components
toc: true
---
## How it works
Here's what you need to know before getting started with the navbar:
- Navbars require a wrapping `.navbar` with `.navbar-expand{-sm|-md|-lg|-xl}` for responsive collapsing and [color scheme](#color-schemes) classes.
- Navbars and their contents are fluid by default. Use [optional containers](#containers) to limit their horizontal width.
- Use our [spacing]({{< docsref "/utilities/spacing" >}}) and [flex]({{< docsref "/utilities/flex" >}}) utility classes for controlling spacing and alignment within navbars.
- Navbars are responsive by default, but you can easily modify them to change that. Responsive behavior depends on our Collapse JavaScript plugin.
- Navbars are hidden by default when printing. Force them to be printed by adding `.d-print` to the `.navbar`. See the [display]({{< docsref "/utilities/display" >}}) utility class.
- Ensure accessibility by using a `<nav>` element or, if using a more generic element such as a `<div>`, add a `role="navigation"` to every navbar to explicitly identify it as a landmark region for users of assistive technologies.
{{< callout info >}}
{{< partial "callout-info-prefersreducedmotion.md" >}}
{{< /callout >}}
## Supported content
Navbars come with built-in support for a handful of sub-components. Choose from the following as needed:
- `.navbar-brand` for your company, product, or project name.
- `.navbar-nav` for a full-height and lightweight navigation (including support for dropdowns).
- `.navbar-toggler` for use with our collapse plugin and other [navigation toggling](#responsive-behaviors) behaviors.
- `.form-inline` for any form controls and actions.
- `.navbar-text` for adding vertically centered strings of text.
- `.collapse.navbar-collapse` for grouping and hiding navbar contents by a parent breakpoint.
Here's an example of all the sub-components included in a responsive light-themed navbar that automatically collapses at the `lg` (large) breakpoint.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-expanded="false">
Dropdown
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item">
<a class="nav-link disabled">Disabled</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
{{< /example >}}
This example uses [color]({{< docsref "/utilities/colors" >}}) (`bg-light`) and [spacing]({{< docsref "/utilities/spacing" >}}) (`my-2`, `my-lg-0`, `mr-sm-0`, `my-sm-0`) utility classes.
### Brand
The `.navbar-brand` can be applied to most elements, but an anchor works best, as some elements might require utility classes or custom styles.
{{< example >}}
<!-- As a link -->
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
</nav>
<!-- As a heading -->
<nav class="navbar navbar-light bg-light">
<span class="navbar-brand mb-0 h1">Navbar</span>
</nav>
{{< /example >}}
Adding images to the `.navbar-brand` will likely always require custom styles or utilities to properly size. Here are some examples to demonstrate.
{{< example >}}
<!-- Just an image -->
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">
<img src="/docs/{{< param docs_version >}}/assets/brand/bootstrap-solid.svg" width="30" height="30" alt="">
</a>
</nav>
{{< /example >}}
{{< example >}}
<!-- Image and text -->
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">
<img src="/docs/{{< param docs_version >}}/assets/brand/bootstrap-solid.svg" width="30" height="30" class="d-inline-block align-top" alt="">
Bootstrap
</a>
</nav>
{{< /example >}}
### Nav
Navbar navigation links build on our `.nav` options with their own modifier class and require the use of [toggler classes](#toggler) for proper responsive styling. **Navigation in navbars will also grow to occupy as much horizontal space as possible** to keep your navbar contents securely aligned.
Active states—with `.active`—to indicate the current page can be applied directly to `.nav-link`s or their immediate parent `.nav-item`s.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link disabled">Disabled</a>
</li>
</ul>
</div>
</nav>
{{< /example >}}
And because we use classes for our navs, you can avoid the list-based approach entirely if you like.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNavAltMarkup">
<div class="navbar-nav">
<a class="nav-link active" href="#">Home <span class="sr-only">(current)</span></a>
<a class="nav-link" href="#">Features</a>
<a class="nav-link" href="#">Pricing</a>
<a class="nav-link disabled">Disabled</a>
</div>
</div>
</nav>
{{< /example >}}
You can also use dropdowns in your navbar. Dropdown menus require a wrapping element for positioning, so be sure to use separate and nested elements for `.nav-item` and `.nav-link` as shown below.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNavDropdown">
<ul class="navbar-nav">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-expanded="false">
Dropdown link
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
</div>
</nav>
{{< /example >}}
### Forms
Place various form controls and components within a navbar with `.form-inline`.
{{< example >}}
<nav class="navbar navbar-light bg-light">
<form class="form-inline">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</nav>
{{< /example >}}
Immediate child elements of `.navbar` use flex layout and will default to `justify-content: space-between`. Use additional [flex utilities]({{< docsref "/utilities/flex" >}}) as needed to adjust this behavior.
{{< example >}}
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand">Navbar</a>
<form class="form-inline">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</nav>
{{< /example >}}
Input groups work, too:
{{< example >}}
<nav class="navbar navbar-light bg-light">
<form class="form-inline">
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon1">@</span>
</div>
<input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="basic-addon1">
</div>
</form>
</nav>
{{< /example >}}
Various buttons are supported as part of these navbar forms, too. This is also a great reminder that vertical alignment utilities can be used to align different sized elements.
{{< example >}}
<nav class="navbar navbar-light bg-light">
<form class="form-inline">
<button class="btn btn-outline-success" type="button">Main button</button>
<button class="btn btn-sm btn-outline-secondary" type="button">Smaller button</button>
</form>
</nav>
{{< /example >}}
### Text
Navbars may contain bits of text with the help of `.navbar-text`. This class adjusts vertical alignment and horizontal spacing for strings of text.
{{< example >}}
<nav class="navbar navbar-light bg-light">
<span class="navbar-text">
Navbar text with an inline element
</span>
</nav>
{{< /example >}}
Mix and match with other components and utilities as needed.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar w/ text</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarText" aria-controls="navbarText" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarText">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
</ul>
<span class="navbar-text">
Navbar text with an inline element
</span>
</div>
</nav>
{{< /example >}}
## Color schemes
Theming the navbar has never been easier thanks to the combination of theming classes and `background-color` utilities. Choose from `.navbar-light` for use with light background colors, or `.navbar-dark` for dark background colors. Then, customize with `.bg-*` utilities.
<div class="bd-example">
<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor01" aria-controls="navbarColor01" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarColor01">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
</ul>
<form class="form-inline">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-info my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
<nav class="navbar navbar-expand-lg navbar-dark bg-primary">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor02" aria-controls="navbarColor02" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarColor02">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
</ul>
<form class="form-inline">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-light my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
<nav class="navbar navbar-expand-lg navbar-light" style="background-color: #e3f2fd;">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor03" aria-controls="navbarColor03" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarColor03">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Features</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Pricing</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
</ul>
<form class="form-inline">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-primary my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
</div>
```html
<nav class="navbar navbar-dark bg-dark">
<!-- Navbar content -->
</nav>
<nav class="navbar navbar-dark bg-primary">
<!-- Navbar content -->
</nav>
<nav class="navbar navbar-light" style="background-color: #e3f2fd;">
<!-- Navbar content -->
</nav>
```
## Containers
Although it's not required, you can wrap a navbar in a `.container` to center it on a page. Or you can add a container inside the `.navbar` to only center the contents of a [fixed or static top navbar](#placement).
{{< example >}}
<div class="container">
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
</nav>
</div>
{{< /example >}}
When the container is within your navbar, its horizontal padding is removed at breakpoints lower than your specified `.navbar-expand{-sm|-md|-lg|-xl}` class. This ensures we're not doubling up on padding unnecessarily on lower viewports when your navbar is collapsed.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<div class="container">
<a class="navbar-brand" href="#">Navbar</a>
</div>
</nav>
{{< /example >}}
## Placement
Use our [position utilities]({{< docsref "/utilities/position" >}}) to place navbars in non-static positions. Choose from fixed to the top, fixed to the bottom, or stickied to the top (scrolls with the page until it reaches the top, then stays there). Fixed navbars use `position: fixed`, meaning they're pulled from the normal flow of the DOM and may require custom CSS (e.g., `padding-top` on the `<body>`) to prevent overlap with other elements.
Also note that **`.sticky-top` uses `position: sticky`, which [isn't fully supported in every browser](https://caniuse.com/css-sticky)**.
{{< example >}}
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">Default</a>
</nav>
{{< /example >}}
{{< example >}}
<nav class="navbar fixed-top navbar-light bg-light">
<a class="navbar-brand" href="#">Fixed top</a>
</nav>
{{< /example >}}
{{< example >}}
<nav class="navbar fixed-bottom navbar-light bg-light">
<a class="navbar-brand" href="#">Fixed bottom</a>
</nav>
{{< /example >}}
{{< example >}}
<nav class="navbar sticky-top navbar-light bg-light">
<a class="navbar-brand" href="#">Sticky top</a>
</nav>
{{< /example >}}
## Scrolling
Add `.navbar-nav-scroll` to a `.navbar-collapse` (or other navbar sub-component) to enable vertical scrolling within the toggleable contents of a collapsed navbar. By default, scrolling kicks in at `75vh` (or 75% of the viewport height), but you can override that with inline or custom styles. At larger viewports when the navbar is expanded, content will appear as it does in a default navbar.
Please note that this behavior comes with a potential drawback of `overflow`—when setting `overflow-y: auto` (required to scroll the content here), `overflow-x` is the equivalent of `auto`, which will crop some horizontal content.
Here's an example navbar using `.navbar-nav-scroll` with `style="max-height: 100px;"`, with some extra margin utilities for optimum spacing.
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar scroll</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarScroll" aria-controls="navbarScroll" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarScroll">
<ul class="navbar-nav mr-auto my-2 my-lg-0 navbar-nav-scroll" style="max-height: 100px;">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarScrollingDropdown" role="button" data-toggle="dropdown" aria-expanded="false">
Link
</a>
<ul class="dropdown-menu" aria-labelledby="navbarScrollingDropdown">
<li><a class="dropdown-item" href="#">Action</a></li>
<li><a class="dropdown-item" href="#">Another action</a></li>
<li><hr class="dropdown-divider"></li>
<li><a class="dropdown-item" href="#">Something else here</a></li>
</ul>
</li>
<li class="nav-item">
<a class="nav-link disabled">Link</a>
</li>
</ul>
<form class="d-flex">
<input class="form-control mr-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success" type="submit">Search</button>
</form>
</div>
</nav>
{{< /example >}}
## Responsive behaviors
Navbars can use `.navbar-toggler`, `.navbar-collapse`, and `.navbar-expand{-sm|-md|-lg|-xl}` classes to determine when their content collapses behind a button. In combination with other utilities, you can easily choose when to show or hide particular elements.
For navbars that never collapse, add the `.navbar-expand` class on the navbar. For navbars that always collapse, don't add any `.navbar-expand` class.
### Toggler
Navbar togglers are left-aligned by default, but should they follow a sibling element like a `.navbar-brand`, they'll automatically be aligned to the far right. Reversing your markup will reverse the placement of the toggler. Below are examples of different toggle styles.
With no `.navbar-brand` shown at the smallest breakpoint:
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo01" aria-controls="navbarTogglerDemo01" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarTogglerDemo01">
<a class="navbar-brand" href="#">Hidden brand</a>
<ul class="navbar-nav mr-auto mt-2 mt-lg-0">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled">Disabled</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
{{< /example >}}
With a brand name shown on the left and toggler on the right:
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo02" aria-controls="navbarTogglerDemo02" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarTogglerDemo02">
<ul class="navbar-nav mr-auto mt-2 mt-lg-0">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled">Disabled</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
{{< /example >}}
With a toggler on the left and brand name on the right:
{{< example >}}
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo03" aria-controls="navbarTogglerDemo03" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand" href="#">Navbar</a>
<div class="collapse navbar-collapse" id="navbarTogglerDemo03">
<ul class="navbar-nav mr-auto mt-2 mt-lg-0">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item">
<a class="nav-link disabled">Disabled</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
{{< /example >}}
### External content
Sometimes you want to use the collapse plugin to trigger a container element for content that structurally sits outside of the `.navbar` . Because our plugin works on the `id` and `data-target` matching, that's easily done!
{{< example >}}
<div class="fixed-top">
<div class="collapse" id="navbarToggleExternalContent">
<div class="bg-dark p-4">
<h5 class="text-white h4">Collapsed content</h5>
<span class="text-muted">Toggleable via the navbar brand.</span>
</div>
</div>
<nav class="navbar navbar-dark bg-dark">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggleExternalContent" aria-controls="navbarToggleExternalContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
</nav>
</div>
{{< /example >}}
When you do this, we recommend including additional JavaScript to move the focus programmatically to the container when it is opened. Otherwise, keyboard users and users of assistive technologies will likely have a hard time finding the newly revealed content - particularly if the container that was opened comes *before* the toggler in the document's structure. We also recommend making sure that the toggler has the `aria-controls` attribute, pointing to the `id` of the content container. In theory, this allows assistive technology users to jump directly from the toggler to the container it controlsbut support for this is currently quite patchy.