.next() and .addClass() not working in jquery
<p>Hello friends following is my code</p>

<p>HTML</p>

<pre><code> &lt;ul&gt;
    &lt;li&gt;
    &lt;div class="input"&gt;&lt;input name="" type="checkbox" value="" id="a"/&gt;&lt;/div&gt;
    &lt;div &gt;Name of the survey goes here | 35 Points - &lt;span&gt;Begin Survey&lt;/span&gt;&lt;/div&gt; 
    &lt;/li&gt;
&lt;/ul&gt;
</code></pre>

<p>Jquery</p>

<pre><code>&lt;script&gt;
$(document).ready(function(){

    $('#a').click(function(){

    $(this).next('div').addClass('.check_clicked');

    })
})
&lt;/script&gt;
</code></pre>

<p>CSS</p>

<pre><code>.check_clicked
{
    text-decoration:line-through;
    color:#b6a7a7;
}
</code></pre>

<p>I just want to if check box value checked then class <code>.check_clicked</code> should apply on next div </p>
