.col-xs- 超小屏幕 手机 (<768px)
.col-sm- 小屏幕 平板 (≥768px)
.col-md- 中等屏幕 桌面显示器 (≥992px)
.col-lg- 大屏幕 大桌面显示器 (≥1200px)
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous"> <title>Bootstrap Test</title> <style> body { padding-top: 2rem; padding-bottom: 2rem; } h3 { margin-top: 2rem; } .row { margin-bottom: 1rem; } .row .row { margin-top: 1rem; margin-bottom: 0; } [class*="col-"] { padding-top: 1rem; padding-bottom: 1rem; background-color: rgba(86, 61, 124, .15); border: 1px solid rgba(86, 61, 124, .2); } hr { margin-top: 2rem; margin-bottom: 2rem; } </style> </head> <body> <main class="container"> <nav class="navbar navbar-expand-md navbar-dark bg-dark fixed-top"> <a class="navbar-brand" href="#">Navbar</a> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarsExampleDefault" aria-controls="navbarsExampleDefault" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse" id="navbarsExampleDefault"> <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"> <a class="nav-link disabled" href="#">Disabled</a> </li> <li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="http://example.com" id="dropdown01" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dropdown</a> <div class="dropdown-menu" aria-labelledby="dropdown01"> <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> <form class="form-inline my-2 my-lg-0"> <input class="form-control mr-sm-2" type="text" placeholder="Search" aria-label="Search"> <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button> </form> </div> </nav> <h1>Bootstrap grid examples</h1> <p class="lead">Basic grid layouts to get you familiar with building within the Bootstrap grid system.</p> <h3>Five grid tiers</h3> <p>There are five tiers to the Bootstrap grid system, one for each range of devices we support. Each tier starts at a minimum viewport size and automatically applies to the larger devices unless overridden.</p> <div class="row"> <div class="col-sm"> One of three columns </div> <div class="col-sm"> One of three columns </div> <div class="col-sm"> One of three columns </div> </div> <div class="row"> <div class="col-3">col</div> <div class="col-3">col</div> <div class="col-3">col</div> <div class="col-3">col</div> </div> <div class="row"> <div class="col-8">col-8</div> <div class="col-4">col-4</div> </div> </main><!-- /.container --> <table class="table table-striped table-bordered"> <tr><th>No</th><th>Name</th><th>Age</th><th>Gendle</th></tr> <tr><td>001</td><td>Tom</td><td>18</td><td>Male</td></tr> <tr><td>002</td><td>Tom</td><td>18</td><td>Male</td></tr> <tr><td>003</td><td>Tom</td><td>18</td><td>Male</td></tr> <tr><td>004</td><td>Tom</td><td>18</td><td>Male</td></tr> </table> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script> <script src="https://cdn.bootcss.com/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script> <script src="https://cdn.bootcss.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script> </body> </html>