CSS弹性盒模型flex在布局中的应用

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目录
[1]元素居中 [2]两端对齐 [3]底端对齐[4]输入框按钮[5]等分布局[6]自适应布局[7]悬挂布局[8]全屏布局

前面的话

　　前面已经详细介绍过flex弹性盒模型的基本语法和兼容写法，本文将介绍flex在布局中的应用

元素居中

【1】伸缩容器上使用主轴对齐justify-content和侧轴对齐align-items

<style>
.parent{
display: flex;
justify-content: center;
align-items: center;
}
</style>

<div class="parent"  style="background-color: lightgrey; height: 100px; width: 200px;">
<div class="in" style="background-color: lightblue;">DEMO</div>
</div>

【2】在伸缩项目上使用margin:auto

<style>
.parent{
display: flex;
}
.in{
margin: auto;
}
</style>

<div class="parent"  style="background-color: lightgrey;height: 100px;width: 200px;">
<div class="in" style="background-color: lightblue;">DEMO</div>
</div>

两端对齐

<style>
.parent{
display: flex;
justify-content:space-between
}
</style>

<div class="parent"  style="background-color: lightgrey;height: 100px;width: 200px;">
<div class="in" style="background-color: lightblue;">DEMO</div>
<div class="in" style="background-color: lightgreen;">DEMO</div>
<div class="in" style="background-color: lightcyan;">DEMO</div>
<div class="in" style="background-color: lightseagreen;">DEMO</div>
</div>

底端对齐

<style>
.parent{
display: flex;
align-items: flex-end;
}
</style>

<div class="parent"  style="background-color: lightgrey;height: 100px;width: 200px;">
<div class="in" style="background-color: lightblue; height:20px;">DEMO</div>
<div class="in" style="background-color: lightgreen; height:30px;">DEMO</div>
<div class="in" style="background-color: lightcyan; height:40px;">DEMO</div>
<div class="in" style="background-color: lightseagreen; height:50px;">DEMO</div>
</div>

输入框按钮

<style>
.inputBox{
display: flex;
width: 250px;
}
.inputBox-ipt{
flex: 1;
}
</style>

<div class="inputBox">
<input class="inputBox-ipt">
<button class="inputBox-btn">按钮</button>
</div>

等分布局

<style>
body,p{margin: 0;}
.parent{
display: flex;
}
.child{
flex:1;
height: 100px;
}
.child + .child{
margin-left: 20px;
}
</style>

<div class="parent" style="background-color: lightgrey;">
<div class="child" style="background-color: lightblue;">1</div>
<div class="child" style="background-color: lightgreen;">2</div>
<div class="child" style="background-color: lightsalmon;">3</div>
<div class="child" style="background-color: pink;">4</div>
</div>

多列自适应布局

<style>
p{margin: 0;}
.parent{display: flex;}
.left,.center{margin-right: 20px;}
.right{flex: 1;}
</style>

<div class="parent" style="background-color: lightgrey;">
<div class="left" style="background-color: lightblue;">
<p>left</p>
<p>left</p>
</div>
<div class="center" style="background-color: pink;">
<p>center</p>
<p>center</p>
</div>
<div class="right"  style="background-color: lightgreen;">
<p>right</p>
<p>right</p>
</div>
</div>

悬挂布局

<style>
.box{
display: flex;
background-color: lightgrey;
width: 300px;
}
.left{
margin-right: 20px;
background-color: lightblue;
height: 30px;
}
.main{
flex:1;
}
</style>

<div class="box">
<div class="left">左侧悬挂</div>
<div class="main">主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容主要内容</div>
</div>

全屏布局

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.parent{
display: flex;
flex-direction: column;
}
.top,.bottom{
height: 50px;
}
.middle{
display: flex;
flex: 1;
}
.left{
width: 100px;
margin-right: 20px;
}
.right{
flex: 1;
overflow: auto;
}
.right-in{
height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
<div class="top" style="background-color: lightblue;">
<p>top</p>
</div>
<div class="middle" style="background-color: pink;">
<div class="left" style="background-color: orange;">
<p>left</p>
</div>
<div class="right" style="background-color: lightsalmon;">
<div class="right-in">
<p>right</p>
</div>
</div>
</div>
<div class="bottom" style="background-color: lightgreen;">
<p>bottom</p>
</div>
</div>

// var all = document.getElementById('cnblogs_post_body').children;
var select = [];

for(var i = 1; i < all.length; i++){
if(all[i].getAttribute('id')){
if(all[i].getAttribute('id').match(/anchor\d+$/)){
select.push(all[i]);
}
}

}
var wheel = function(e){
e = e || event;
var data;
if(e.wheelDelta){
data = e.wheelDelta;
}else{
data = -e.detail * 40;
}
for(var i = 0; i < select.length; i++){
if(select[i].getBoundingClientRect().top > 0){
return;
}
if(select[i].getBoundingClientRect().top <= 0 && select[i+1]){
if(select[i+1].getBoundingClientRect().top > 0){
change(oCon.children[i+2])
}
}else{
change(oCon.children[select.length+1])
}
}

}
document.body.onmousewheel = wheel;
document.body.addEventListener('DOMMouseScroll',wheel,false);

var oCon = document.getElementById("content");
var close = oCon.getElementsByTagName('span')[0];
close.onclick = function(){
if(this.innerHTML == '显示目录'){
this.innerHTML = '×';
this.style.background = '';
oCon.style.border = '2px solid #ccc';
oCon.style.width = '';
oCon.style.height = '';
oCon.style.overflow = '';
oCon.style.lineHeight = '30px';
}else{
this.innerHTML = '显示目录';
this.style.background = '#3399ff';
oCon.style.border = 'none';
oCon.style.width = '60px';
oCon.style.height = '30px';
oCon.style.overflow = 'hidden';
oCon.style.lineHeight = '';
}
}
for(var i = 2; i < oCon.children.length; i++){
oCon.children[i].onmouseover = function(){
this.style.color = '#3399ff';
}
oCon.children[i].onmouseout = function(){
this.style.color = 'inherit';
if(this.mark){
this.style.color = '#3399ff';
}

}
oCon.children[i].onclick = function(){
change(this);
}
}

function change(_this){
for(var i = 2; i < oCon.children.length; i++){
oCon.children[i].mark = false;
oCon.children[i].style.color = 'inherit';
oCon.children[i].style.textDecoration = 'none';
oCon.children[i].style.borderColor = 'transparent';
}
_this.mark = true;
_this.style.color = '#3399ff';
_this.style.textDecoration = 'underline';
_this.style.borderColor = '#2175bc';
}
// ]]>