How to add class on td trough Jquery
<p>I have below html</p>

<pre><code>&lt;table class="Newuser" cellspacing="0" cellpadding="0" border="0" id="ctl00_ContentPlaceHolder2_CreateUserWizard1"&gt;
&lt;tr&gt;
    &lt;td&gt;
     &lt;table&gt;
      &lt;tr&gt;
       &lt;td&gt;
       &lt;/td&gt;
       &lt;td&gt;
       &lt;/td&gt;
      &lt;/tr&gt;
     &lt;/table&gt;
    &lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
    &lt;td&gt;
     &lt;table&gt;
      &lt;tr&gt;
       &lt;td&gt;
       &lt;/td&gt;
       &lt;td&gt;
       &lt;/td&gt;
      &lt;/tr&gt;
     &lt;/table&gt;
     &lt;/td&gt;
    &lt;/tr&gt;
&lt;/table&gt;
</code></pre>

<p>Now I want to add a class on runtime through Jquery so that my update code will become as below. I want to add a <strong>class</strong> on second tr first td whose main class is <strong>"Newuser"</strong></p>

<pre><code>&lt;table class="Newuser" cellspacing="0" cellpadding="0" border="0" id="ctl00_ContentPlaceHolder2_CreateUserWizard1"&gt;
&lt;tr&gt;
    &lt;td&gt;
     &lt;table&gt;
      &lt;tr&gt;
       &lt;td&gt;
       &lt;/td&gt;
       &lt;td&gt;
       &lt;/td&gt;
      &lt;/tr&gt;
     &lt;/table&gt;
    &lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
    &lt;td&gt;
     &lt;table&gt;
      &lt;tr&gt;
       &lt;td class="buttonClose"&gt;
       &lt;/td&gt;
       &lt;td&gt;
       &lt;/td&gt;
      &lt;/tr&gt;
     &lt;/table&gt;
     &lt;/td&gt;
    &lt;/tr&gt;
&lt;/table&gt;
</code></pre>

<p>Please suggest!</p>
