Bootstrap: Div with 100% width inside container - html

Question

I want to create a div with full-width of the browser.
The div is inside a container and I couldn't change that structure.
Now the div inside the container has only the width of the container. Even if I set it to position: absolute like here: How to create a 100% screen width div inside a container in bootstrap?
The div is a dropdown-menu inside the bootstrap navbar.
Is there any solution to get it to 100% of the screen size? Is there anything inside the navbar what changes the position/width?
This is my code:
.dropdown-menu {min-width: 100%; position: absolute; display:block;}
<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet"/>
<div class="container">
<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
<button class="navbar-toggler navbar-toggler-right" 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>
<a class="navbar-brand" href="#">Navbar</a>
<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="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" 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>
</div>

Answer 1

CSS has a unit vw, which stands for viewport width. 1vw represents 1% of the screen width.
Therefore, you can set width: 100vw to take up 100% of the screen width.
Update
For current markup you can set position: fixed, but you'll have to set correct top value manually. Unfortunately if your page is more than screen height your menu will keep the same position. Demo:
body {
margin: 0;
}
.dropdown-menu {
position: fixed !important;
top: 56px;
right: 0;
left: 0;
}
#media (max-width: 991px) {
.navbar-toggleable-md .navbar-nav .dropdown-menu {
top: 215px;
}
}
<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
<button class="navbar-toggler navbar-toggler-right" 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>
<a class="navbar-brand" href="#">Navbar</a>
<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="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" 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>
</div>
To achieve desired markup, you'll have to remove position: relative for all ancestors to apply absolute positioning relatively to window. So you'll have to fix all issues with this. Also you'll have to set top manually (because you are setting absolute positioning relatively to to window). Demo:
/* delete relatively position */
.container,
.navbar,
.nav-item {
position: static !important;
}
/* set absolute positioning */
.dropdown-menu {
position: absolute !important;
top: 55px !important;
left: 0;
right: 0;
}
#media (max-width: 991px) {
/* add centering for extra container */
.flex-center {
display: flex;
align-items: center;
}
/* fix positioning for toggler */
/* it will be broken to removed relative positioning for container */
.navbar-toggler-right {
position: static !important;
margin-left: auto;
margin-right: 1rem;
}
.navbar-toggleable-md .navbar-nav .dropdown-menu {
top: 215px !important;
}
}
<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
<div class="flex-center">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler navbar-toggler-right" 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>
<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="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" 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>
</div>