how to use php add a class to the code?
<pre><code>&lt;div class="centerBox"&gt;
&lt;div class="centerBox line-y"&gt;
&lt;div class="centerBox line_y"&gt;
&lt;div class="centerBox"&gt;
&lt;div class="centerBox line_y"&gt;
&lt;div class="centerBox line_y"&gt;
&lt;div class="centerBox"&gt;
&lt;div class="centerBox line_y"&gt;
&lt;div class="centerBox line_y"&gt;
</code></pre>

<p>I want to use  loop to add a class named <code>line_y</code> to the above code, how should i do? thank you.</p>

<p>add  <code>line-y</code> to 2,3,5,6,8,9 lines</p>
