三栏式布局(所谓的圣杯和双飞翼) - 小火柴的蓝色理想
前面的话
常常听说圣杯布局和双飞翼布局,以为是两个很高级的语汇。但实际上,他们只是三栏式布局的两种布局方法而已。本文将介绍三栏式布局的3种思路
思路一: float
【1】圣杯布局
圣杯布局使用float、负margin和relative,不需要添加额外标签。.main元素设置padding,为两侧定宽元素留出位置。内容元素设置100%宽度,占据中间位置。而两侧定宽元素通过设置负margin和relative的偏移属性配合,到达相应位置
缺点: 并没有实现等高布局;使用了相对定位,扩展性不好
<span style="color: #0000ff;"><span style="color: #800000;">style</span><span style="color: #0000ff;">></span><span style="background-color: #f5f5f5; color: #800000;"> body,p</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .top,.bottom</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 30px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .middle</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> padding</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0 120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> overflow</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> hidden</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left,.right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> position</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> relative</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span> <span style="color: #0000ff;"></span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span></span>
<span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgrey;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="top"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightblue;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>top<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="middle"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: pink;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="main"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcoral;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="left"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: orange;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>left<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="right"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightsalmon;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>right<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bottom"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgreen;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>bottom<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
【2】双飞翼布局
双飞翼布局在圣杯布局的基础上,通过为.main元素外添加一层div结构,不使用相对定位。在.main元素上设置margin。两侧的定宽列通过负margin来占据.main元素的margin区域
缺点: 并没有实现等高布局,增加了html结构
<span style="color: #0000ff;"><span style="color: #800000;">style</span><span style="color: #0000ff;">></span><span style="background-color: #f5f5f5; color: #800000;"> body,p</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .top,.bottom</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 30px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .middle</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">overflow</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> hidden</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .mainWrap</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0 120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left,.right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span> <span style="color: #0000ff;"></span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span></span>
<span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgrey;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="top"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightblue;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>top<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="middle"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: pink;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="mainWrap"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="main"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcoral;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="left"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: orange;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>left<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="right"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightsalmon;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>right<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bottom"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgreen;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>bottom<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
【3】float + box-sizing + background-clip
.main元素的border区域为两侧定宽列的所在区域,实现伪等高效果;设置.main的padding和background-clip来实现元素间隔。两侧元素通过负margin调整到.main元素的border区域
缺点: 兼容性不好
<span style="color: #0000ff;"><span style="color: #800000;">style</span><span style="color: #0000ff;">></span><span style="background-color: #f5f5f5; color: #800000;"> body,p</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .top,.bottom</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 30px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .middle</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">overflow</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> hidden</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> border-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px solid lightgrey</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> border-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px solid lightgrey</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> padding</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0 20px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> background-clip</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> content-box</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> box-sizing</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> border-box</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left,.right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> float</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> left</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100%</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span> <span style="color: #0000ff;"></span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span></span>
<span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgrey;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="top"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightblue;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>top<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="middle"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: pink;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="main"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcoral;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="left"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>left<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="right"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>right<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bottom"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgreen;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>bottom<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
思路二: absolute
设置子元素的top:0;bottom:0;使得所有子元素的高度都和父元素的高度相同,实现等高效果
缺点: 需要为.middle元素设置高度,扩展性较差
<span style="color: #0000ff;"><span style="color: #800000;">style</span><span style="color: #0000ff;">></span><span style="background-color: #f5f5f5; color: #800000;"> body,p</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .top,.bottom</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 30px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .middle</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> position</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> relative</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 40px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left,.right,.main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> position</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> absolute</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> top</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 120px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span> <span style="color: #0000ff;"></span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span></span>
<span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgrey;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="top"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightblue;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>top<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="middle"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: pink;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="main"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcoral;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="left"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightseagreen;"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>left<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="right"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcyan;"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>right<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bottom"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgreen;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>bottom<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
思路三: flex
flex中的伸缩项目默认都拉伸为父元素的高度,可实现等高效果。通过改变伸缩项目的order,可以实现元素顺序调换的效果
缺点: 兼容性不高
<span style="color: #0000ff;"><span style="color: #800000;">style</span><span style="color: #0000ff;">></span><span style="background-color: #f5f5f5; color: #800000;"> body,p</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .top,.bottom</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 30px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .middle</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">display</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> flex</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .left,.right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">width</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 100px</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .right</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;">order</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 2</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #000000;">}</span><span style="background-color: #f5f5f5; color: #800000;"> .main</span><span style="background-color: #f5f5f5; color: #000000;">{</span><span style="background-color: #f5f5f5; color: #ff0000;"> order</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 1</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> flex</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 1</span><span style="background-color: #f5f5f5; color: #000000;">;</span><span style="background-color: #f5f5f5; color: #ff0000;"> margin</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 0 20px</span><span style="background-color: #f5f5f5; color: #000000;">;</span> <span style="background-color: #f5f5f5; color: #000000;">}</span> <span style="color: #0000ff;"></span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span></span>
<span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="parent"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgrey;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="top"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightblue;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>top<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="middle"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: pink;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="main"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcoral;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>main<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="left"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightseagreen;"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>left<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="right"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightcyan;"</span> <span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>right<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bottom"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="background-color: lightgreen;"</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>bottom<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
总结
由于限定了主要内容元素在html结构中位于前面,通过css样式改变将其位置调换到中间的前提,所以思路并不是很多。float浮动流的元素可以通过负margin调换位置;absolute绝对定位流的元素可以通过偏移属性调换位置;flex弹性盒模型可以通过order属性调换位置。而处于正常流中的元素除了使用relative外,使用负margin是无法调换位置的,所以table、inline-block等布局方式在此前提下不是很实用。

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159

The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.

The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati

The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex

Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.

The article discusses the <iframe> tag's purpose in embedding external content into webpages, its common uses, security risks, and alternatives like object tags and APIs.

This article explains the HTML5 <time> element for semantic date/time representation. It emphasizes the importance of the datetime attribute for machine readability (ISO 8601 format) alongside human-readable text, boosting accessibilit

The article discusses the viewport meta tag, essential for responsive web design on mobile devices. It explains how proper use ensures optimal content scaling and user interaction, while misuse can lead to design and accessibility issues.
