Bootstrap 4 .flex-*-fill类的实现
使用flex-*-fill类将flex项目设置为在不同屏幕上具有相等的宽度，如下面的代码片段所示-
对于 小宽度的屏幕
<div class="d-flex mb-3 bg-primary"> <div class="p-2 flex-sm-fill bg-info">A</div> <div class="p-2 flex-sm-fill bg-warning">B</div> <div class="p-2 flex-sm-fill bg-primary">C</div> </div>
对于中等宽度的屏幕
<div class="d-flex mb-3 bg-primary"> <div class="p-2 flex-md-fill bg-info">A</div> <div class="p-2 flex-md-fill bg-warning">B</div> <div class="p-2 flex-md-fill bg-primary">C</div> </div>
以下是实现flex-*fill类的示例-
枫树
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h3>Flex (Small Width)</h3>
<div class="d-flex mb-3 bg-primary">
<div class="p-2 flex-sm-fill bg-info">A</div>
<div class="p-2 flex-sm-fill bg-warning">B</div>
<div class="p-2 flex-sm-fill bg-primary">C</div>
</div>
<h3>Flex (Medium Width)</h3>
<div class="d-flex mb-3 bg-primary">
<div class="p-2 flex-md-fill bg-info">A</div>
<div class="p-2 flex-md-fill bg-warning">B</div>
<div class="p-2 flex-md-fill bg-primary">C</div>
</div>
<h3>Flex (Large Width)</h3>
<div class="d-flex mb-3 bg-primary">
<div class="p-2 flex-lg-fill bg-info">A</div>
<div class="p-2 flex-lg-fill bg-warning">B</div>
<div class="p-2 flex-lg-fill bg-primary">C</div>
</div>
</div>
</body>
</html>