在这章我们将学习到：

1.盒子模式的复杂和特征
2.怎样并且为什么页边空白收缩
3.绝对位置和相对位置的不同
4.floating 和 clearing怎样工作

Box model recap

* {
margin: 0;
padding: 0;
}

#myBox {
margin: 10px;
padding: 5px;
width: 70px;
}

Margin collapsing

Positioning recap

Relative positioning 相对位置

#myBox {
position: relative;
left: 20px;
top: 20px;
}

Absolute positioning 绝对位置

#branding {
width: 700px;
height: 100px;
position: relative;
}
#branding .tel {
position: absolute;
right: 10px;
bottom: 10px;
text-align: right;
}
<div id="branding">
<p class="tel">Tel: 0845 838 6163</p>
</div>

Floating




Line boxes and clearing

.news {
background-color: gray;
border: solid 1px black;
}
.news img {
float: left;
}
.news p {
float: right;
}
<div class="news">
<img src="news-pic.jpg" />
<p>Some text</p>
</div>

.news {
background-color: gray;
border: solid 1px black;
}
.news img {
float: left;
}
.news p {
float: right;
}
.clear {
clear: both;
}
<div class="news">
<img src="news-pic.jpg" />
<p>Some text</p>
<div class="clear"></div>
</div>

更简捷的方法如下:

.news {
background-color: gray;
border: solid 1px black;
float: left;
}
.news img {
float: left;
}

.news p {
float: right;
}
<div class="news">
<img src="news-pic.jpg" />
<p>Some text</p>
</div>