CSS marging浅析-html教程-PHP中文网

<span style="color: #008080;"> 1</span> <span style="color: #0000ff;"><!</span><span style="color: #ff00ff;">DOCTYPE html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 2</span> <span style="color: #0000ff;"><</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 3</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 4</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">meta </span><span style="color: #ff0000;">charset</span><span style="color: #0000ff;">="utf-8"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 5</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>不改变DOM结构的流体布局<span style="color: #0000ff;"></</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 6</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 7</span> <span style="background-color: #f5f5f5; color: #800000;">            .container </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;"> 8</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;">600px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;"> 9</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;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">10</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">11</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> orange</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">12</span> <span style="background-color: #f5f5f5; color: #ff0000;">                font-size</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 16px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">13</span> <span style="background-color: #f5f5f5; color: #ff0000;">                line-height</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 1.5</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">14</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">15</span> 
<span style="color: #008080;">16</span> <span style="background-color: #f5f5f5; color: #800000;">            .box1 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">17</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="color: #008080;">18</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="color: #008080;">19</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">20</span> 
<span style="color: #008080;">21</span> <span style="background-color: #f5f5f5; color: #800000;">            .box2 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">22</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 220px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">23</span> <span style="background-color: #f5f5f5; color: #ff0000;">                padding-left</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 20px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">24</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">25</span> 
<span style="color: #008080;">26</span> <span style="background-color: #f5f5f5; color: #800000;">            img </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">27</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;">200px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">28</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="color: #008080;">29</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;">-200px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">30</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">31</span> 
<span style="color: #008080;">32</span> <span style="background-color: #f5f5f5; color: #800000;">            .clearfix:after </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">33</span> <span style="background-color: #f5f5f5; color: #ff0000;">                content</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> ""</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">34</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;"> table</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">35</span> <span style="background-color: #f5f5f5; color: #ff0000;">                clear</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> both</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">36</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">37</span> 
<span style="color: #008080;">38</span> <span style="background-color: #f5f5f5; color: #800000;">            .clearfix </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">39</span> <span style="background-color: #f5f5f5; color: #ff0000;">                *zoom</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="color: #008080;">40</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">41</span> 
<span style="color: #008080;">42</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">43</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">44</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">45</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="container clearfix"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">46</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box1"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">47</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box2"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">48</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">h3</span><span style="color: #0000ff;">></span>不改变DOM位置的流体布局<span style="color: #0000ff;"></</span><span style="color: #800000;">h3</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">49</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>假如有一段文本和一幅图像，在DOM节点中，文本在前，图像在后，怎么能把图像定位到右边呢？<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">50</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>通常的做法是，调换DOM节点中图像与文本的位置，让图像在前，文本在后，然后将图像浮动到右边即可。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">51</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>但这样改变DOM节点顺序始终不妥，还有什么更好的方法呢？<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">52</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>下面就介绍一种新的思路来完成布局。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">53</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">ul</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">54</span>                     <span style="color: #0000ff;"><</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>将文本用div包起来，定义为box1；现在的结构是一个box1和一个img。<span style="color: #0000ff;"></</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">55</span>                     <span style="color: #0000ff;"><</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>将box1宽度设为100%，左浮动；将img设置一个宽度，也左浮动，然后margin-left设为负的宽度值；此时图像就定位到文本的右边啦。<span style="color: #0000ff;"></</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">56</span>                     <span style="color: #0000ff;"><</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>但是有一个问题，图像盖住了文本内容，这可怎么办？<span style="color: #0000ff;"></</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">57</span>                     <span style="color: #0000ff;"><</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>重点来了，在box1中增加一个box2，box2把文本全部包起来，然后margin-right设为图像的宽度（+额外的间距），这样就解决问题啦！<span style="color: #0000ff;"></</span><span style="color: #800000;">li</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">58</span>                 <span style="color: #0000ff;"></</span><span style="color: #800000;">ul</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">59</span>                 <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span><span style="color: #008000;"><!--</span><span style="color: #008000;">关闭box2</span><span style="color: #008000;">--></span>
<span style="color: #008080;">60</span>             <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span><span style="color: #008000;"><!--</span><span style="color: #008000;">关闭box1</span><span style="color: #008000;">--></span>
<span style="color: #008080;">61</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">img </span><span style="color: #ff0000;">src</span><span style="color: #0000ff;">="http://imgsrc.baidu.com/forum/w%3D580/sign=0c101fe665380cd7e61ea2e59145ad14/f9a3492762d0f7032de1758a08fa513d2797c542.jpg"</span><span style="color: #ff0000;"> alt</span><span style="color: #0000ff;">="a picture"</span><span style="color: #ff0000;"> style</span><span style="color: #0000ff;">="width:200px;height:300px"</span> <span style="color: #0000ff;">/></span>
<span style="color: #008080;">62</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span><span style="color: #008000;"><!--</span><span style="color: #008000;">关闭container</span><span style="color: #008000;">--></span>
<span style="color: #008080;">63</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">64</span> <span style="color: #0000ff;"></</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>

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<span style="color: #008080;"> 1</span> <span style="color: #0000ff;"><!</span><span style="color: #ff00ff;">DOCTYPE html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 2</span> <span style="color: #0000ff;"><</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 3</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 4</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">meta </span><span style="color: #ff0000;">charset</span><span style="color: #0000ff;">="utf-8"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 5</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>margin负值实现等高布局<span style="color: #0000ff;"></</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 6</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 7</span> <span style="background-color: #f5f5f5; color: #800000;">            div.container </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;"> 8</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;"> 200px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;"> 9</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="color: #008080;">10</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">11</span> 
<span style="color: #008080;">12</span> <span style="background-color: #f5f5f5; color: #800000;">            div.box </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">13</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;">300px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">14</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="color: #008080;">15</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 20px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">16</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">17</span> 
<span style="color: #008080;">18</span> <span style="background-color: #f5f5f5; color: #800000;">            div.box1 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">19</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> brown</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">20</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -9999px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">21</span> <span style="background-color: #f5f5f5; color: #ff0000;">                padding-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 9999px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">22</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">23</span> 
<span style="color: #008080;">24</span> <span style="background-color: #f5f5f5; color: #800000;">            div.box2 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">25</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> green</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">26</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> -9999px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">27</span> <span style="background-color: #f5f5f5; color: #ff0000;">                padding-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 9999px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">28</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">29</span> 
<span style="color: #008080;">30</span> <span style="background-color: #f5f5f5; color: #800000;">            p </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">31</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 50px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">32</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">33</span> 
<span style="color: #008080;">34</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">35</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">36</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">37</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="container"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">38</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box box1"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">39</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box1<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">40</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box1<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">41</span>             <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">42</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box box2"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">43</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">44</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">45</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">46</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">47</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">48</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">49</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">50</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>box2<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">51</span>             <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">52</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="container"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">53</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">54</span> <span style="color: #0000ff;"></</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>

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<span style="color: #008080;"> 1</span> <span style="color: #0000ff;"><!</span><span style="color: #ff00ff;">DOCTYPE html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 2</span> <span style="color: #0000ff;"><</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 3</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 4</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">meta </span><span style="color: #ff0000;">charset</span><span style="color: #0000ff;">="utf-8"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 5</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>margin的百分数值<span style="color: #0000ff;"></</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 6</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 7</span> <span style="background-color: #f5f5f5; color: #800000;">            .container </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;"> 8</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;"> 500px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;"> 9</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;"> 300px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">10</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;"> 50px auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">11</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> orange</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">12</span> <span style="background-color: #f5f5f5; color: #ff0000;">                border</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 1px solid black</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">13</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">14</span> 
<span style="color: #008080;">15</span> <span style="background-color: #f5f5f5; color: #800000;">            .box </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">16</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;"> 250px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">17</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;"> 150px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">18</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;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">19</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">20</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> cyan</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">21</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">22</span> 
<span style="color: #008080;">23</span> <span style="background-color: #f5f5f5; color: #800000;">            .box1 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">24</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-top</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 75px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">25</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 75px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">26</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;"> 5px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">27</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">28</span>             
<span style="color: #008080;">29</span> <span style="background-color: #f5f5f5; color: #800000;">            .box2 </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">30</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-top</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 25%</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">31</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-bottom</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 25%</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">32</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;"> 5px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">33</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">34</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">35</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">36</span> 
<span style="color: #008080;">37</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">38</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="container"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">39</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box box1"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">40</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>父元素的高度为300px，子元素的高度为150px，只要margin-top和margin-bottom都为75px，这个盒子就能垂直居中。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">41</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>OK，居中啦！！！<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">42</span>             <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">43</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">44</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="container"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">45</span>             <span style="color: #0000ff;"><</span><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="box box2"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">46</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>既然子元素的高度是父元素高度的50%，那么只要margin-top和margin-bottom都为25%，应该也能垂直居中。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">47</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>额，这什么鬼？说好的居中呢？<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">48</span>             <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">49</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">50</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">51</span> <span style="color: #0000ff;"></</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>

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<span style="color: #008080;"> 1</span> <span style="color: #0000ff;"><!</span><span style="color: #ff00ff;">DOCTYPE html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 2</span> <span style="color: #0000ff;"><</span><span style="color: #800000;">html</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 3</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 4</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">meta </span><span style="color: #ff0000;">charset</span><span style="color: #0000ff;">="utf-8"</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 5</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>垂直方向上的margin合并<span style="color: #0000ff;"></</span><span style="color: #800000;">title</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 6</span>         <span style="color: #0000ff;"><</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;"> 7</span> <span style="background-color: #f5f5f5; color: #800000;">            .container </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;"> 8</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;"> 500px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;"> 9</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;"> 300px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">10</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;"> 50px auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">11</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> orange</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">12</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">13</span> 
<span style="color: #008080;">14</span> <span style="background-color: #f5f5f5; color: #800000;">            .box </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">15</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;"> 300px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">16</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;"> 200px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">17</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;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">18</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-right</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> auto</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">19</span> <span style="background-color: #f5f5f5; color: #ff0000;">                background-color</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> cyan</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">20</span> <span style="background-color: #f5f5f5; color: #ff0000;">                margin-top</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 25px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">21</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;"> 5px</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">22</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">23</span> 
<span style="color: #008080;">24</span> <span style="background-color: #f5f5f5; color: #800000;">            .border </span><span style="background-color: #f5f5f5; color: #000000;">{</span>
<span style="color: #008080;">25</span> <span style="background-color: #f5f5f5; color: #ff0000;">                border</span><span style="background-color: #f5f5f5; color: #000000;">:</span><span style="background-color: #f5f5f5; color: #0000ff;"> 1px solid black</span><span style="background-color: #f5f5f5; color: #000000;">;</span>
<span style="color: #008080;">26</span>                 <span style="background-color: #f5f5f5; color: #008000;">/*</span><span style="background-color: #f5f5f5; color: #008000;">padding: 1px;</span><span style="background-color: #f5f5f5; color: #008000;">*/</span>
<span style="color: #008080;">27</span>             <span style="background-color: #f5f5f5; color: #000000;">}</span>
<span style="color: #008080;">28</span>         <span style="color: #0000ff;"></</span><span style="color: #800000;">style</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">29</span>     <span style="color: #0000ff;"></</span><span style="color: #800000;">head</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">30</span> 
<span style="color: #008080;">31</span>     <span style="color: #0000ff;"><</span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
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<span style="color: #008080;">34</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>父元素的margin-top为50px，子元素的margin-top为25px；<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">35</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>咦，子元素的margin-top呢？为什么都顶到父元素上边界了？<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">36</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>额，因为父元素与子元素的margin-top亲密接触了呀，所以它们合并在一起了啊。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
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<span style="color: #008080;">41</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>可是我就是想让子元素距离父元素的上边界25px啊，我不想让它们合并呀。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">42</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>很简单，给父元素加个边框，它们就无法亲密接触了，就不会合并了啊。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #008080;">43</span>                 <span style="color: #0000ff;"><</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>或者给父元素设置padding也是可以的喔。<span style="color: #0000ff;"></</span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
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