html css twitter-bootstrap bootstrap-4 background-image

Bootstrap 4 background image full-height with navbar no scrolling

I have a page with a navbar. I want to add a responsive background image to the page (not the navbar).

If I set the page to 100% height it overflows the page with a scrollbar.

How should this be accomplished? I have no idea.

.bg { 
    /* The image used */
    background-image: url("http://via.placeholder.com/350x150");


    /* Center and scale the image nicely */
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet"/>

<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" href="#">Disabled</a>
      </li>
    </ul>
  </div>
</nav>

<div class="main-page">
  <div class="bg"></div>
  <div class="data">
    bla bla bla
  </div>

</div>

Edit: jsfiddle - JSFIDDLE

Solution

You can use the Bootstrap 4 flexbox utils, and add flex:1 1 auto to the main-page so it fills the height (with no scrolling).

https://www.codeply.com/go/isN2cS0m0q

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" ></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
    
<style>
body {
    min-height: 100vh;
}
.flex-fill {
   flex: 1 1 auto;
}  
.bg { 
    background-image: url("http://placehold.it/350x150");
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
}
</style>
<body class="d-flex flex-column">
<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" href="#">Disabled</a>
            </li>
        </ul>
    </div>
</nav>
<div class="main-page d-flex flex-column flex-fill">
    <div class="bg flex-fill"></div>
    <div class="data">
        bla bla bla
    </div>
</div>
</body>

Note: The flex-fill class will be included in Bootstrap 4.1 so the extra CSS for flex-fill will no longer be needed when 4.1 is released.