我有一个基本的Web应用程序，它有一个数据表.
<table id="period_table" class="table table-striped table-bordered table-hover table-condensed table-sm display nowrap display compact" cellspacing="0" width="100%">
<thead>
<tr>
<th>Date</th>
<th>Name</th>
<th>Number</th>
<th>Price</th>
</tr>
</thead>
</table>问题:我想把我的桌子4分成4条.我的意思是前4行是灰色的，下4行是白色的，然后下4行又是灰色的."表条纹化"类仅对1*1进行条纹化.
你可以用nth-child加上一系列公式(8n+k)，n从0开始:
`8n+1` will select row 1 - 9 - 17 ...
`8n+2` will select row 2 - 10 - 18 ...
`8n+3` will select row 3 - 11 - 19 ...
`8n+4` will select row 4 - 12 - 20 ...
最终，我们会得出预期的结果.
tbody > tr:nth-child(8n+1),
tbody > tr:nth-child(8n+2),
tbody > tr:nth-child(8n+3),
tbody > tr:nth-child(8n+4) {
background: gray;
}<table id="period_table" class="table table-bordered table-hover table-condensed table-sm display nowrap display compact" cellspacing="0" width="100%">
<thead>
<tr>
<th>Name</th>
<th>Position</th>
<th>Office</th>
<th>Age</th>
<th>Start date</th>
<th>Salary</th>
</tr>
</thead>
<tbody>
<tr>
<td>Tiger Nixon</td>
<td>System Architect</td>
<td>Edinburgh</td>
<td>61</td>
<td>2011-04-25</td>
<td>$320,800</td>
</tr>
<tr>
<td>Garrett Winters</td>
<td>Accountant</td>
<td>Tokyo</td>
<td>63</td>
<td>2011-07-25</td>
<td>$170,750</td>
</tr>
<tr>
<td>Ashton Cox</td>
<td>Junior Technical Author</td>
<td>San Francisco</td>
<td>66</td>
<td>2009-01-12</td>
<td>$86,000</td>
</tr>
<tr>
<td>Cedric Kelly</td>
<td>Senior Javascript Developer</td>
<td>Edinburgh</td>
<td>22</td>
<td>2012-03-29</td>
<td>$433,060</td>
</tr>
<tr>
<td>Airi Satou</td>
<td>Accountant</td>
<td>Tokyo</td>
<td>33</td>
<td>2008-11-28</td>
<td>$162,700</td>
</tr>
<tr>
<td>Brielle Williamson</td>
<td>Integration Specialist</td>
<td>New York</td>
<td>61</td>
<td>2012-12-02</td>
<td>$372,000</td>
</tr>
<tr>
<td>Herrod Chandler</td>
<td>Sales Assistant</td>
<td>San Francisco</td>
<td>59</td>
<td>2012-08-06</td>
<td>$137,500</td>
</tr>
<tr>
<td>Rhona Davidson</td>
<td>Integration Specialist</td>
<td>Tokyo</td>
<td>55</td>
<td>2010-10-14</td>
<td>$327,900</td>
</tr>
<tr>
<td>Colleen Hurst</td>
<td>Javascript Developer</td>
<td>San Francisco</td>
<td>39</td>
<td>2009-09-15</td>
<td>$205,500</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
<tr>
<td>Sonya Frost</td>
<td>Software Engineer</td>
<td>Edinburgh</td>
<td>23</td>
<td>2008-12-13</td>
<td>$103,600</td>
</tr>
</tbody>
</table>