Bootstrap3 API CHM，探索其功能与应用

Introduction

Bootstrap is a popular front-end framework for developing responsive and mobile-first websites. This cheat sheet provides a quick reference to the most commonly used classes, components, and utilities in Bootstrap 3. Whether you are new to Bootstrap or need a quick refresher, this guide will help you streamline your development process.

Layout

Grid System

Bootstrap's grid system uses a series of containers, rows, and columns to create responsive layouts. It's built with a 12-column grid, making it easy to create complex layouts.

Class Prefix	Description	Example
`.col-xs`	Extra small devices (phones, less than 768px)	`.col-xs-12`
`.col-sm`	Small devices (tablets, 768px and up)	`.col-sm-6`
`.col-md`	Medium devices (desktops, 992px and up)	`.col-md-4`
`.col-lg`	Large devices (large desktops, 1200px and up)	`.col-lg-3`

Example

<div class="container">
  <div class="row">
    <div class="col-xs-12 col-sm-6 col-md-4">Column 1</div>
    <div class="col-xs-12 col-sm-6 col-md-4">Column 2</div>
    <div class="col-xs-12 col-sm-6 col-md-4">Column 3</div>
  </div>
</div>

Components

Buttons

Bootstrap includes several types of buttons for different contexts. You can customize their appearance using various classes.

Class	Description	Example
`.btn`	Standard button
`.btn-primary`	Primary action button
`.btn-success`	Successful action button
`.btn-info`	Informational button
`.btn-warning`	Warning button
`.btn-danger`	Dangerous action button

Forms

Bootstrap provides styles for forms to ensure they look good on all devices.

Class	Description	Example
`.form-control`	Apply to form controls for styling
`.form-group`	Group label and control together	`Example input`
`.has-error`	Add error state	`Input with error`

Utilities

Text Alignment

Bootstrap offers utility classes for text alignment within any element.

Class	Description	Example
`.text-left`	Align text to the left	`Left aligned text`
`.text-center`	Center align text	`Center aligned text`
`.text-right`	Align text to the right	`Right aligned text`
`.text-justify`	Justify text	`Justified text`
`.text-nowrap`	Prevent text from wrapping	`No wrap text`

Visibility Classes

These classes control the visibility of elements based on screen size.

Class	Description	Example
`.visible-xs`	Always visible	`Always visible`
`.visible-sm`	Visible on small devices	`Visible on small devices`
`.visible-md`	Visible on medium devices	`Visible on medium devices`
`.visible-lg`	Visible on large devices	`Visible on large devices`
`.hidden-xs`	Hidden on extra small devices	`Hidden on extra small devices`
`.hidden-sm`	Hidden on small devices	`Hidden on small devices`
`.hidden-md`	Hidden on medium devices	`Hidden on medium devices`
`.hidden-lg`	Hidden on large devices	`Hidden on large devices`

Colors

Bootstrap comes with a set of predefined color classes that can be applied to any element.

Class	Description	Example
`.text-muted`	Set text to a muted grey color	`Muted text`
`.text-primary`	Set text to primary color	`Primary text`
`.text-success`	Set text to success color	`Success text`
`.text-info`	Set text to info color	`Info text`
`.text-warning`	Set text to warning color	`Warning text`
`.text-danger`	Set text to danger color	`Danger text`

Questions and Answers

Q1: How do I make a button disabled in Bootstrap?

A1: You can use thedisabled attribute along with the appropriate button classes to disable a button:

<button class="btn btn-primary" disabled>Disabled Button</button>

This renders a primary button that is visually styled as disabled and non-interactive.

Q2: How can I center an element horizontally using Bootstrap?

A2: To center an element horizontally, you can use the.text-center utility class:

<div class="text-center">
  <h1>Centered Heading</h1>
</div>

Alternatively, you can use the grid system to center elements by placing them in a column with offset classes, like so:

<div class="container">
  <div class="row">
    <div class="col-md-offset-4 col-md-4">Centered Content</div>
  </div>
</div>

到此，以上就是小编对于“bootstrap3 api chm”的问题就介绍到这了，希望介绍的几点解答对大家有用，有任何问题和不懂的，欢迎各位朋友在评论区讨论，给我留言。

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