快速开始
css
复制粘贴样式表到head
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
integrity
包含行内元数据,它是一个你用浏览器获取的资源文件的哈希值,以base64编码的方式加的密,这样用户能用它来验证一个获取到的资源,在传送时未被非法篡改,详情查看Subresource Integrity。
简单说就是防止CDN篡改javascript用的
“anonymous”会发起一个跨域请求(即包含 Origin: HTTP 头). 但不会发送任何认证信息 (即不发送 cookie, X.509 证书和 HTTP 基本认证信息). 如果服务器没有给出源站凭证 (不设置 Access-Control-Allow-Origin: HTTP 头), 这张图片就会被污染并限制使用.
参考连接: https://imququ.com/post/subre…
JS
依赖jQuery,Popper.js,bootstrap自身插件
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
顺序要一致
注意:bootstrap.bundle.js
包含了Popper,不包含jQuery
模板
<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<title>Hello, world!</title>
</head>
<body>
<h1>Hello, world!</h1>
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
</body>
</html>
响应式meta标签
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
Box-sizing
将属性值改为:
{
box-sizing: content-box ---> border-box
}
Layout
Containers
源码
.container {
width: 100%;
padding-right: 15px;
padding-left: 15px;
margin-right: auto;
margin-left: auto;
}
在页面中.container
不是占满全屏的
@media (min-width: 576px) {
.container {
max-width: 540px;
}
}
@media (min-width: 768px) {
.container {
max-width: 720px;
}
}
@media (min-width: 992px) {
.container {
max-width: 960px;
}
}
@media (min-width: 1200px) {
.container {
max-width: 1140px;
}
}
媒体查询设置max-width
的断点导致左右居中
应该有计算公式,后面再说
使用containe-fulid
占满整个视窗
Z-index
以下组件都使用z-index
$zindex-dropdown: 1000 !default;
$zindex-sticky: 1020 !default;
$zindex-fixed: 1030 !default;
$zindex-modal-backdrop: 1040 !default;
$zindex-modal: 1050 !default;
$zindex-popover: 1060 !default;
$zindex-tooltip: 1070 !default;
栅格系统
原理:基于flex布局和媒体查询
官方代码片段
<div class="container">
<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>
先说.row
.row {
//
display: -webkit-box; /* Chrome 4+, Safari 3.1, iOS Safari 3.2+ */
display: -ms-flexbox; /* IE 10 */
display: flex;
-ms-flex-wrap: wrap;
flex-wrap: wrap;
margin-right: -15px;
margin-left: -15px;
}
可以看出css实现的兼容;还有margin左右各取-15px,这里我理解为拉长.row元素自身的宽度,跟.container达成一致
再看下.col-sm
// 所有的columns类名的共有属性
.col-1, .col-2, .col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-9, .col-10, .col-11, .col-12, .col,
.col-auto, .col-sm-1, .col-sm-2, .col-sm-3, .col-sm-4, .col-sm-5, .col-sm-6, .col-sm-7, .col-sm-8, .col-sm-9, .col-sm-10, .col-sm-11, .col-sm-12, .col-sm,
.col-sm-auto, .col-md-1, .col-md-2, .col-md-3, .col-md-4, .col-md-5, .col-md-6, .col-md-7, .col-md-8, .col-md-9, .col-md-10, .col-md-11, .col-md-12, .col-md,
.col-md-auto, .col-lg-1, .col-lg-2, .col-lg-3, .col-lg-4, .col-lg-5, .col-lg-6, .col-lg-7, .col-lg-8, .col-lg-9, .col-lg-10, .col-lg-11, .col-lg-12, .col-lg,
.col-lg-auto, .col-xl-1, .col-xl-2, .col-xl-3, .col-xl-4, .col-xl-5, .col-xl-6, .col-xl-7, .col-xl-8, .col-xl-9, .col-xl-10, .col-xl-11, .col-xl-12, .col-xl,
.col-xl-auto {
position: relative;
width: 100%;
min-height: 1px;
padding-right: 15px;
padding-left: 15px;
}
@media (min-width: 576px) {
.col-sm {
-ms-flex-preferred-size: 0;
flex-basis: 0;
-webkit-box-flex: 1;
-ms-flex-positive: 1;
flex-grow: 1;
max-width: 100%;
}
}
先说第一个知识点,ming-height: 1px
,这个东东有什么用的,简单的说,就是当.col-sm
的元素不包含文本时,不会发生水平折叠的尴尬现象,这里我参考大佬的文章
放心,我不写flex属性:)
这里先说下5大layout,分别是extra small(<576px),small(≥576px),medium(≥768px),large(≥992px),extra large(≥1200px)。.col-sm
适合除extra small之外的。
.no-gutter
消除columns的padding以及.row
的margin
.no-gutters {
margin-right: 0;
margin-left: 0;
}
.no-gutters > .col,
.no-gutters > [class*="col-"] {
padding-right: 0;
padding-left: 0;
}
等宽
.col
适用于所有的layout
.col {
-ms-flex-preferred-size: 0;
flex-basis: 0;
-webkit-box-flex: 1;
-ms-flex-positive: 1;
flex-grow: 1;
max-width: 100%;
}
这里注意max-width
与flex-grow
的结合占满viewport!
.w-100
.w-100 {
width: 100% !important;
}
小技巧,可以强制换行
<div class="container">
<div class="row">
<div class="col">Column</div>
<div class="col">Column</div>
<div class="w-100"></div>
<div class="col">Column</div>
<div class="col">Column</div>
</div>
</div>
适应内容的宽度
.col-{breakpoint}-auto
.col-md-auto {
-webkit-box-flex: 0;
-ms-flex: 0 0 auto;
flex: 0 0 auto;
width: auto;
max-width: none;
}
这一column的宽度是由内容撑开!
Alignment
<div class="container">
<div class="row align-items-start">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
<div class="row align-items-center">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
<div class="row align-items-end">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
</div>
控制.row的位置
//发现.align-items-stretch和.align-items-baseline文档并没有指出
.align-items-start {
-webkit-box-align: start !important;
-ms-flex-align: start !important;
align-items: flex-start !important;
}
.align-items-end {
-webkit-box-align: end !important;
-ms-flex-align: end !important;
align-items: flex-end !important;
}
.align-items-center {
-webkit-box-align: center !important;
-ms-flex-align: center !important;
align-items: center !important;
}
.align-items-baseline {
-webkit-box-align: baseline !important;
-ms-flex-align: baseline !important;
align-items: baseline !important;
}
.align-items-stretch {
-webkit-box-align: stretch !important;
-ms-flex-align: stretch !important;
align-items: stretch !important;
}
更多align-item的区别可以参考这篇文章
以及控制align-self的类
.align-self-auto {
-ms-flex-item-align: auto !important;
align-self: auto !important;
}
.align-self-start {
-ms-flex-item-align: start !important;
align-self: flex-start !important;
}
.align-self-end {
-ms-flex-item-align: end !important;
align-self: flex-end !important;
}
.align-self-center {
-ms-flex-item-align: center !important;
align-self: center !important;
}
.align-self-baseline {
-ms-flex-item-align: baseline !important;
align-self: baseline !important;
}
.align-self-stretch {
-ms-flex-item-align: stretch !important;
align-self: stretch !important;
}
水平方向排列
<div class="container">
<div class="row justify-content-start">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-center">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-end">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-around">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-between">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
</div>
通过控制justify-content来控制
.justify-content-sm-start {
-webkit-box-pack: start !important;
-ms-flex-pack: start !important;
justify-content: flex-start !important;
}
.justify-content-sm-end {
-webkit-box-pack: end !important;
-ms-flex-pack: end !important;
justify-content: flex-end !important;
}
.justify-content-sm-center {
-webkit-box-pack: center !important;
-ms-flex-pack: center !important;
justify-content: center !important;
}
.justify-content-sm-between {
-webkit-box-pack: justify !important;
-ms-flex-pack: justify !important;
justify-content: space-between !important;
}
.justify-content-sm-around {
-ms-flex-pack: distribute !important;
justify-content: space-around !important;
}
通过order-*控制列的顺序
.order-first {
-webkit-box-ordinal-group: 0;
-ms-flex-order: -1;
order: -1;
}
.order-last {
-webkit-box-ordinal-group: 14;
-ms-flex-order: 13;
order: 13;
}
.order-0 {
-webkit-box-ordinal-group: 1;
-ms-flex-order: 0;
order: 0;
}
.order-1 {
-webkit-box-ordinal-group: 2;
-ms-flex-order: 1;
order: 1;
}
.order-2 {
-webkit-box-ordinal-group: 3;
-ms-flex-order: 2;
order: 2;
}
.order-3 {
-webkit-box-ordinal-group: 4;
-ms-flex-order: 3;
order: 3;
}
.order-4 {
-webkit-box-ordinal-group: 5;
-ms-flex-order: 4;
order: 4;
}
.order-5 {
-webkit-box-ordinal-group: 6;
-ms-flex-order: 5;
order: 5;
}
.order-6 {
-webkit-box-ordinal-group: 7;
-ms-flex-order: 6;
order: 6;
}
.order-7 {
-webkit-box-ordinal-group: 8;
-ms-flex-order: 7;
order: 7;
}
.order-8 {
-webkit-box-ordinal-group: 9;
-ms-flex-order: 8;
order: 8;
}
.order-9 {
-webkit-box-ordinal-group: 10;
-ms-flex-order: 9;
order: 9;
}
.order-10 {
-webkit-box-ordinal-group: 11;
-ms-flex-order: 10;
order: 10;
}
.order-11 {
-webkit-box-ordinal-group: 12;
-ms-flex-order: 11;
order: 11;
}
.order-12 {
-webkit-box-ordinal-group: 13;
-ms-flex-order: 12;
order: 12;
}
偏移
示例
<div class="row">
<div class="col-md-4">.col-md-4</div>
<div class="col-md-4 offset-md-4">.col-md-4 .offset-md-4</div>
</div>
<div class="row">
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
</div>
<div class="row">
<div class="col-md-6 offset-md-3">.col-md-6 .offset-md-3</div>
</div>
都是设置margin-left的百分比控制偏移量
.offset-md-0 {
margin-left: 0;
}
.offset-md-1 {
margin-left: 8.333333%;
}
.offset-md-2 {
margin-left: 16.666667%;
}
.offset-md-3 {
margin-left: 25%;
}
.offset-md-4 {
margin-left: 33.333333%;
}
.offset-md-5 {
margin-left: 41.666667%;
}
.offset-md-6 {
margin-left: 50%;
}
.offset-md-7 {
margin-left: 58.333333%;
}
.offset-md-8 {
margin-left: 66.666667%;
}
.offset-md-9 {
margin-left: 75%;
}
.offset-md-10 {
margin-left: 83.333333%;
}
.offset-md-11 {
margin-left: 91.666667%;
}
后面都是讲scss定制,暂时忽略