使用 Switch 语句可以避免冗长的 if..elseif..else 代码块。
PHP Switch语句工作原理：
对表达式（通常是变量）进行一次计算
把表达式的值与结构中 case 的值进行比较
如果存在匹配，则执行与 case 关联的代码
代码执行后，break 语句阻止代码跳入下一个 case 中继续执行
如果没有 case 为真，则使用 default 语句
<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> ?php </span></span></span></li>
<li>
<span>switch ($</span><span class="attribute">d</span><span>=</span><span class="attribute-value">date</span><span>("D")) </span>
</li>
<li class="alt"><span>{ </span></li>
<li><span>case "Mon"; </span></li>
<li class="alt"><span>echo "周一"; </span></li>
<li><span>break; </span></li>
<li class="alt"><span>case "Tue"; </span></li>
<li><span>echo "周二"; </span></li>
<li class="alt"><span>break; </span></li>
<li><span>case "Wed"; </span></li>
<li class="alt"><span>echo "周三"; </span></li>
<li><span>break; </span></li>
<li class="alt"><span>case "Thu"; </span></li>
<li><span>echo "周四"; </span></li>
<li class="alt"><span>break; </span></li>
<li><span>case "Fir"; </span></li>
<li class="alt"><span>echo "周五"; </span></li>
<li><span>break; </span></li>
<li class="alt"><span>case "Sat"; </span></li>
<li><span>echo "周六"; </span></li>
<li class="alt"><span>break; </span></li>
<li><span>case "Sun"; </span></li>
<li class="alt"><span>echo "周日"; </span></li>
<li><span>break; </span></li>
<li class="alt"><span>} </span></li>
<li>
<span class="tag">?></span><span> </span>
</li>
</ol>另外一个实例，利用PHP Switch语句实现一个页面多用途，首先建立test.php页面：
<ol class="dp-xml"> <li class="alt"><span><span class="tag"><span> ?php </span></span></span></li> <li> <span>echo "</span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=</span><span class="attribute-value">'solution.php?<br>action=add'</span><span class="tag">></span><span>增加</span><span class="tag"><span> /a</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span>"; </span></span></span></span></span> </li> <li class="alt"> <span>echo "</span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=</span><span class="attribute-value">'solution.php?<br>action=del'</span><span class="tag">></span><span>删除</span><span class="tag"><span> /a</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span>"; </span></span></span></span></span> </li> <li> <span>echo "</span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=</span><span class="attribute-value">'solution.php?<br>action=search'</span><span class="tag">></span><span>查找</span><span class="tag"><span> /a</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span class="tag"><span> </span><span class="tag-name">br</span><span class="tag">></span><span>"; </span></span></span></span></span> </li> <li class="alt"> <span>echo "</span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=</span><span class="attribute-value">'solution.php?<br>action=update'</span><span class="tag">></span><span>更新</span><span class="tag"><span> /a</span><span class="tag">></span><span>"; </span></span></span> </li> <li> <span class="tag">?></span><span> </span> </li> <li class="alt"><span> </span></li> </ol>
当然PHP Switch语句这里sunec省略了其他大部分的代码，只是把其中一些提交按钮写了出来。我们可以看到，无论点击哪个按钮，我们都会跳转到solution.php页面，唯一不不同的是，问号后的action的内容分成了4种。我们可以把它称作是一种提示。
