php不支持属性值的问题

在改写主题时，遇到了比较烦的问题:

<code> <li><a class="active" href="#"></a></li></code>

PHP文件中插入了这个代码就会报错:

[16-Aug-2016 13:45:49 UTC] PHP Parse error: syntax error, unexpected 'active' (T_STRING), expecting ',' or ';' in /home/sunhbjaq/public_html/site/snippets/sidebar.php on line 17

当把class="active"去掉后就会恢复正常。
请问该如何解决？谢谢。（新手，请耐心回答，非常感谢！）
注:sidebar.php全文:

<code><!-- header -->            <section id="header">                <header>                    
<span class="image avatar"><img src="<?php%20echo%20html(%24site->authoravatarurl())%20?>" alt="<?php echo html($site->description()) ?>"></span>                    
<h1 id="logo"><a href="<?php%20echo%20%24site->authorurl>"><?php echo html($site->author()) ?></a></h1>                    <p><?php echo html($site->authorintroduction()) ?></p>                
</header>
<!-- /header 下面为id-->   <nav>         
<ul>          
<?php foreach($pages->visible() as $p): ?>          <?php if ($p->isOpen()): ?>              <li><a class="active" href="#"></a></li>          <?php else: ?>              <li><a href="<?php%20echo%20html(%24p->url())%20?>"></a></li>          <?php endif; ?>          <?php endforeach ?>      </ul>   </nav>   <footer>                    <ul class="icons">                        <li><a href="#" class="icon fa-twitter"><span class="label">Twitter</span></a></li>                        <li><a href="#" class="icon fa-facebook"><span class="label">Facebook</span></a></li>                        <li><a href="#" class="icon fa-instagram"><span class="label">Instagram</span></a></li>                        <li><a href="#" class="icon fa-github"><span class="label">Github</span></a></li>                        <li><a href="#" class="icon fa-envelope"><span class="label">Email</span></a></li>                    </ul>     </footer></section></code>

回复内容：

在改写主题时，遇到了比较烦的问题:

<code> <li><a class="active" href="#"></a></li></code>

PHP文件中插入了这个代码就会报错:

[16-Aug-2016 13:45:49 UTC] PHP Parse error: syntax error, unexpected 'active' (T_STRING), expecting ',' or ';' in /home/sunhbjaq/public_html/site/snippets/sidebar.php on line 17

当把class="active"去掉后就会恢复正常。
请问该如何解决？谢谢。（新手，请耐心回答，非常感谢！）
注:sidebar.php全文:

<code><!-- header -->            <section id="header">                <header>                    
<span class="image avatar"><img src="<?php%20echo%20html(%24site->authoravatarurl())%20?>" alt="<?php echo html($site->description()) ?>"></span>                    
<h1 id="logo"><a href="<?php%20echo%20%24site->authorurl>"><?php echo html($site->author()) ?></a></h1>                    <p><?php echo html($site->authorintroduction()) ?></p>                
</header>
<!-- /header 下面为id-->   <nav>         
<ul>          
<?php foreach($pages->visible() as $p): ?>          <?php if ($p->isOpen()): ?>              <li><a class="active" href="#"></a></li>          <?php else: ?>              <li><a href="<?php%20echo%20html(%24p->url())%20?>"></a></li>          <?php endif; ?>          <?php endforeach ?>      </ul>   </nav>   <footer>                    <ul class="icons">                        <li><a href="#" class="icon fa-twitter"><span class="label">Twitter</span></a></li>                        <li><a href="#" class="icon fa-facebook"><span class="label">Facebook</span></a></li>                        <li><a href="#" class="icon fa-instagram"><span class="label">Instagram</span></a></li>                        <li><a href="#" class="icon fa-github"><span class="label">Github</span></a></li>                        <li><a href="#" class="icon fa-envelope"><span class="label">Email</span></a></li>                    </ul>     </footer></section></code>

你这是语法错误，请上代码谢谢。