div的垂直居中 - dzxczx

<span style="color: #008080;"> 1</span> <span style="color: #800000;">.diva</span>{
<span style="color: #008080;"> 2</span> <span style="color: #ff0000;">      width</span>:<span style="color: #0000ff;">300px</span>;
<span style="color: #008080;"> 3</span> <span style="color: #ff0000;">      height</span>:<span style="color: #0000ff;">300px</span>;
<span style="color: #008080;"> 4</span> <span style="color: #ff0000;">      background-color</span>:<span style="color: #0000ff;">green</span>;
<span style="color: #008080;"> 5</span> <span style="color: #ff0000;">      position</span>:<span style="color: #0000ff;">absolute</span>;
<span style="color: #008080;"> 6</span> <span style="color: #ff0000;">      top</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;"> 7</span> <span style="color: #ff0000;">      right</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;"> 8</span> <span style="color: #ff0000;">      bottom</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;"> 9</span> <span style="color: #ff0000;">      left</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;">10</span> <span style="color: #ff0000;">      margin</span>:<span style="color: #0000ff;">auto</span>;
<span style="color: #008080;">11</span> }
<span style="color: #008080;">12</span> <span style="color: #800000;">这是一种垂直居中的方式。
</span><span style="color: #008080;">13</span> 
<span style="color: #008080;">14</span> <span style="color: #800000;">第二种兼容比较好
</span><span style="color: #008080;">15</span> 
<span style="color: #008080;">16</span> <span style="color: #800000;">.divb</span>{
<span style="color: #008080;">17</span> <span style="color: #ff0000;">      width</span>:<span style="color: #0000ff;">300px</span>;
<span style="color: #008080;">18</span> <span style="color: #ff0000;">      height</span>:<span style="color: #0000ff;">300px</span>;
<span style="color: #008080;">19</span> <span style="color: #ff0000;">      background-color</span>:<span style="color: #0000ff;">red</span>;
<span style="color: #008080;">20</span> <span style="color: #ff0000;">      position</span>:<span style="color: #0000ff;">absolute</span>;
<span style="color: #008080;">21</span> <span style="color: #ff0000;">      top</span>:<span style="color: #0000ff;">50%</span>;
<span style="color: #008080;">22</span> <span style="color: #ff0000;">      right</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;">23</span> <span style="color: #ff0000;">      left</span>:<span style="color: #0000ff;">0</span>;
<span style="color: #008080;">24</span> <span style="color: #ff0000;">      margin</span>:<span style="color: #0000ff;">auto</span>;
<span style="color: #008080;">25</span> <span style="color: #ff0000;">      margin-top</span>:<span style="color: #0000ff;">-150px</span>;<span style="color: #ff0000;">//一半的高度
</span><span style="color: #008080;">26</span> }