Bootstrap 4 provides different styles of buttons:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 4 Button 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/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Bootstrap Button Styles</h2>
<button type="button" class="btn">Basic</button>
<button type="button" class="btn btn-primary">Primary</button>
<button type="button" class="btn btn-secondary">Secondary</button>
<button type="button" class="btn btn-success">Success</button>
<button type="button" class="btn btn-info">Info</button>
<button type="button" class="btn btn-warning">Warning</button>
<button type="button" class="btn btn-danger">Danger</button>
<button type="button" class="btn btn-dark">Dark</button>
<button type="button" class="btn btn-light">Light</button>
<button type="button" class="btn btn-link">Link</button>
</div>
</body>
</html>
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Bootstrap 4 provides eight outline/bordered buttons:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 4 button outline 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/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Button Outline</h2>
<button type="button" class="btn btn-outline-primary">Primary</button>
<button type="button" class="btn btn-outline-secondary">Secondary</button>
<button type="button" class="btn btn-outline-success">Success</button>
<button type="button" class="btn btn-outline-info">Info</button>
<button type="button" class="btn btn-outline-warning">Warning</button>
<button type="button" class="btn btn-outline-danger">Danger</button>
<button type="button" class="btn btn-outline-dark">Dark</button>
<button type="button" class="btn btn-outline-light text-dark">Light</button>
</div>
</body>
</html>
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Use the .btn-lg class for large buttons or .btn-sm class for small buttons:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 4 Button Sizes 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/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Button Sizes</h2>
<button type="button" class="btn btn-primary btn-lg">Large</button>
<button type="button" class="btn btn-primary btn-md">Default</button>
<button type="button" class="btn btn-primary btn-sm">Small</button>
</div>
</body>
</html>
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Add class .btn-block to create a block level button that spans the entire width of the parent element.
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 4 Block Level 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/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Block Level Buttons</h2>
<button type="button" class="btn btn-primary btn-block">Button 1</button>
<button type="button" class="btn btn-success btn-block">Button 2</button>
<br>
<h2>Large Block Level Buttons</h2>
<button type="button" class="btn btn-primary btn-lg btn-block">Button 1</button>
<button type="button" class="btn btn-success btn-lg btn-block">Button 2</button>
<br>
<h2>Small Block Level Buttons</h2>
<button type="button" class="btn btn-primary btn-sm btn-block">Button 1</button>
<button type="button" class="btn btn-success btn-sm btn-block">Button 2</button>
</div>
</body>
</html>
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<!DOCTYPE html>
<html>
<head>
<title>Bootstrap 4 Spinner Buttons Example</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Spinner Buttons</h2>
<p>Add spinners to buttons:</p>
<button class="btn btn-primary">
<span class="spinner-border spinner-border-sm"></span>
</button>
<button class="btn btn-primary">
<span class="spinner-border spinner-border-sm"></span>
Loading..
</button>
<button class="btn btn-primary" disabled>
<span class="spinner-border spinner-border-sm"></span>
Loading..
</button>
<button class="btn btn-primary" disabled>
<span class="spinner-grow spinner-grow-sm"></span>
Loading..
</button>
</div>
</body>
</html>
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