编程实现盒模型的基本要素: 内容，内外边距与边框，并背诵padding与margin的简写规则；
实例
<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>内容外边距内边距</title> <!--编程实现盒模型的基本要素: 内容，内外边距与边框，并背诵padding与margin的简写规则；--> </head> <style> .box{ width: 400px; height:400px; background-color: lightgreen; border: 5px solid #888888; padding-top: 15px; padding-bottom: 50px; padding-left: 2em; padding-right: 30px; } .box2{ width:200px; height:200px; background-color: firebrick; margin: 18px 32px; } </style> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
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编程实现最常用的四种元素对齐方案；
实例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>元素对齐方式</title>
</head>
<body>
<style>
/*子元素是单行行内元素*/
.box1{
width:200px;
height:200px;
background-color: #39FF1B;
text-align: center;
}
.box1 span{
line-height: 200px;
}
</style>
<div class="box1">
<span>PHP天下第一</span>
</div>
<hr>
<!--多行文本居中-->
<style>
.box2{
width:200px;
height:200px;
background-color: powderblue;
display: table-cell;
text-align: center;
vertical-align: middle;
}
</style>
<div class="box2">
<p>PHP天下第一</p>
<p>PHP宇宙无敌</p>
</div>
<hr>
<style>
.box3{
width:200px;
height:200px;
background-color: olivedrab;
display: table-cell;
vertical-align: middle; /*垂直居中*/
}
.box3 .child {
width:100px;
height:100px;
background-color: #FFE80E;
margin: auto;
}
</style>
<div class="box3">
<div class="child"></div>
</div>
<br>
<!--子元素是定宽块元素-->
<style>
.box4 {
width: 200px;
height: 200px;
background-color: lightblue;
text-align: center; /*水平居中*/
display: table-cell;
vertical-align: bottom; /*位于底部*/
}
ul {
margin: 0;
padding-left: 0;
}
.box4 li {
display: inline; /*将块元素转为行内元素*/
}
</style>
<div class="box4">
<ul>
<li><a href="">1</a></li>
<li><a href="">2</a></li>
<li><a href="">3</a></li>
<li><a href="">4</a></li>
<li><a href="">5</a></li>
</ul>
</div>
</body>
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3.编程实现用五个色块制作一个十字架(相对定位和绝对定位任选一种实现即可)
实例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>用绝对定位做十字架</title>
</head>
<body>
<style>
.box{
position: relative;
}
.box1{
width: 200px;
height: 200px;
background-color: #FFE80E;
position: absolute;
top: 0;
left: 200px;
}
.box2{
width: 200px;
height: 200px;
background-color: lightgreen;
position: absolute;
top: 200px;
left: 0;
}
.box3{
width: 200px;
height: 200px;
background-color: rebeccapurple;
position: absolute;
top: 400px;
left: 200px;
}
.box4{
width: 200px;
height: 200px;
background-color: pink;
position: absolute;
top: 200px;
left:400px ;
}
</style>
<div class="box">
<div class="box1"></div>
<div class="box2"></div>
<div class="box3"></div>
<div class="box4"></div>
</div>
</body>
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