一丶盒模型的属性(重要)
1.padding
padding是标准文档流,父子之间调整位置


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>paddingtitle>
<style>
*{
padding: 0;
margin: 0;
}
.box{
width: 200px;
height: 200px;
background-color: red;
/*上下左右*/
padding: 10px;
/*上下 左右*/
padding: 20px 30px;
/*上 左右 下*/
padding: 20px 30px 40px;
/*顺时针 上右下左*/
padding: 20px 30px 40px 50px;
}
style>
head>
<body>
<div class="box">alexdiv>
body>
html>
2.border
三要素: 线性的宽度 线性的样式 颜色
solid 实线 dotted小圆点 double双实线 bottom虚线


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>bordertitle>
<style>
*{
padding: 0;
margin: 0;
}
.box{
width: 200px;
height: 200px;
background-color: red;
/*根据方向来设置*/
border-left: 5px solid green;
border-right: 1px dotted yellow;
border-top: 5px double purple;
border-bottom: 1px dashed;
}
style>
head>
<body>
<div class="box">alexdiv>
body>
html>
实例:制作三角形
transparent 透明


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>制作三角形title>
<style type="text/css">
div{
width: 0;
height: 0;
border-bottom: 20px solid red;
border-left: 20px solid transparent;
border-right: 20px solid transparent;
}
style>
head>
<body>
<div>
div>
body>
html>
3.margin
前提:必须是在标准文档流下


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>margintitle>
<style>
.s1{
background-color: red;
margin-right: 30px;
}
.s2{
background-color: rgb(0,128,0);
margin-left: 30px;
}
style>
head>
<body>
<span class="s1">alexspan><span class="s2">wusirspan>
body>
html>
margin垂直方向上的坑:
margin的水平不会出现任何问题
垂直方向上 margin会出现'塌陷问题'


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>margin坑title>
<style>
.s1{
width: 200px;
height: 200px;
background-color: red;
margin-bottom: 40px;
}
.s2{
width: 200px;
height: 200px;
background-color: green;
margin-top: 100px;
}
style>
head>
<body>
<div class="s1">div>
<div class="s2">div>
body>
html>


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>margin父子盒子的坑title>
<style type="text/css">
.box{
width: 300px;
height: 300px;
background-color: red;
/*float: left;*/
}
.child{
width: 100px;
height: 100px;
background-color: green;
margin-left: 50px;
margin-top: 50px;
}
style>
head>
<body>
<div class="father">
<div class="child">
div>
div>
body>
html>
二丶display显示
前提;必须是在标准文档流下
块级元素和行内元素的相互转换:
块级元素可以转换为行内元素:
display:inline
此时这个div不能设置宽度丶高度;
此时这个div可以和别人并排了
行内元素转换为块级元素:
display:block
此时这个span能够设置宽高
此时这个span必须霸占一行了,别人无法和他并排
如果不设置宽度,将撑满父亲


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>displaytitle>
<style>
.box{
width: 100px;
height: 100px;
background-color: red;
border: 1px solid yellow;
}
div a{
display: block;
width: 100px;
height: 100px;
}
span{
display: inline-block;
width: 300px;
height: 200px;
background-color: yellow;
}
style>
head>
<body>
<div class="box">alexdiv>
<div class="box">wusirdiv>
<div>
<a href="#">
<img src="http://img07.tooopen.com/images/20170818/tooopen_sy_220999936848.jpg" alt="" width="300" height="300"/>
a>
div>
<input type="text" /><br />
<span>哈哈哈哈span>
<span>嘻嘻嘻嘻span>
body>
html>
三丶浮动
float : none 表示不浮动,默认
left:表示左浮动
right:表示右浮动


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>浮动title>
<style>
*{
padding: 0;
margin: 0;
}
.father{
width: 500px;
}
.box1{
width: 100px;
height: 100px;
background-color:red;
float: left;
}
.box2{
width: 100px;
height: 300px;
background-color:green;
float: left;
}
.box3{
width: 100px;
height: 100px;
background-color:blue;
float: left;
}
.father2{
width: 600px;
height: 200px;
background-color: yellow;
}
style>
head>
<body>
<div class="father">
<div class="box1">1div>
<div class="box2">2div>
<div class="box3">3div>
div>
<div class="father2">
div>
body>
html>
我们该如何清除浮动呢?有以下几种方法


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>清除浮动title>
<style>
*{
padding: 0;
margin: 0;
}
.father{
width: 500px;
height: 300px;
}
.box1{
width: 100px;
height: 100px;
background-color:red;
float: left;
}
.box2{
width: 100px;
height: 300px;
background-color:green;
float: left;
}
.box3{
width: 100px;
height: 100px;
background-color:blue;
float: left;
}
.father2{
width: 600px;
height: 200px;
background-color: yellow;
}
style>
head>
<body>
<div class="father">
<div class="box1">1div>
<div class="box2">2div>
<div class="box3">3div>
div>
<div class="father2">
div>
body>
html>


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>清除浮动title>
<style>
*{
padding: 0;
margin: 0;
}
.father{
width: 500px;
}
.box1{
width: 100px;
height: 100px;
background-color:red;
float: left;
}
.box2{
width: 100px;
height: 300px;
background-color:green;
float: left;
}
.box3{
width: 100px;
height: 100px;
background-color:blue;
float: left;
}
.father2{
width: 600px;
height: 200px;
background-color: yellow;
}
.clearfix{
clear:both;
}
style>
head>
<body>
<div class="father">
<div class="box1">1div>
<div class="box2">2div>
<div class="box3">3div>
<div class="clearfix">div>
div>
<div class="father2">
div>
body>
html>
visibility:hidden; 设为隐藏


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>伪元素清除法title>
<style>
*{
padding: 0;
margin: 0;
}
.father{
width: 500px;
}
.box1{
width: 100px;
height: 100px;
background-color:red;
float: left;
}
.box2{
width: 100px;
height: 300px;
background-color:green;
float: left;
}
.box3{
width: 100px;
height: 100px;
background-color:blue;
float: left;
}
.father2{
width: 600px;
height: 200px;
background-color: yellow;
}
.clearfix:after{
content: '.';
clear: both;
display: block;
visibility: hidden;
height: 0;
}
style>
head>
<body>
<div class="box">
<div class="father clearfix">
<div class="box1">1div>
<div class="box2">2div>
<div class="box3">3div>
div>
div>
<div class="father2">div>
body>
html>


DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>伪元素清除法title>
<style>
*{
padding: 0;
margin: 0;
}
.father{
width: 500px;
overflow: hidden;
}
.box1{
width: 100px;
height: 100px;
background-color:red;
float: left;
}
.box2{
width: 100px;
height: 300px;
background-color:green;
float: left;
}
.box3{
width: 100px;
height: 100px;
background-color:blue;
float: left;
}
.father2{
width: 600px;
height: 200px;
background-color: yellow;
}
style>
head>
<body>
<div class="box">
<div class="father">
<div class="box1">1div>
<div class="box2">2div>
<div class="box3">3div>
div>
div>
<div class="father2">div>
body>
html>