Select exact number of table td after a radiobutton is checked
<p>I have a multistep form, where in one step I select the whole number (1–X) with which I can work in the next step. In the next step I have a table of days of a week (I only show a shortened version here). Some of the cells contain radiobuttons. </p>

<p>What I want to do is: if I select one of the radiobuttons I need to add a class to the exact number of column TD which are below this one (where I checked the radio).
Here is an example of the table:</p>

<pre><code>&lt;table&gt;
    &lt;thead&gt;
        &lt;tr&gt;
            &lt;th&gt;&lt;/th&gt;
            &lt;th&gt;Úterý&lt;br /&gt;06.12.2011&lt;/th&gt;
           &lt;th&gt;Středa&lt;br /&gt;07.12.2011&lt;/th&gt;
       &lt;/tr&gt;
    &lt;/thead&gt;
    &lt;tbody&gt;
        &lt;tr class="odd"&gt;
            &lt;td&gt;08:00&lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-wrapper"&gt;
                &lt;label class="option" for="edit-datetime-worker"&gt;
                &lt;input type="radio" id="edit-datetime-worker" name="datetime_worker" value="2011-12-06T08:00:00::3"   class="form-radio" /&gt;
                &lt;span&gt;6. 12. 2011 – 08:00&lt;/span&gt;&lt;/label&gt;
                &lt;/div&gt;
            &lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-11-wrapper"&gt;
                &lt;label class="option" for="edit-datetime-worker-11"&gt;
                &lt;input type="radio" id="edit-datetime-worker-11" name="datetime_worker" value="2011-12-07T08:00:00::3"   class="form-radio" /&gt;
                &lt;span&gt;7. 12. 2011 – 08:00&lt;/span&gt;&lt;/label&gt;
                &lt;/div&gt;
            &lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr class="even"&gt;
            &lt;td&gt;08:30&lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-1-wrapper"&gt;&lt;/div&gt;&lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-12-wrapper"&gt;
                &lt;label class="option" for="edit-datetime-worker-12"&gt;
                &lt;input type="radio" id="edit-datetime-worker-12" name="datetime_worker" value="2011-12-07T08:30:00::3"   class="form-radio" /&gt;
                &lt;span&gt;7. 12. 2011 – 08:30&lt;/span&gt;&lt;/label&gt;
                &lt;/div&gt;
            &lt;/td&gt;
        &lt;/tr&gt;
        &lt;tr class="odd"&gt;
            &lt;td&gt;09:00&lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-2-wrapper"&gt;
                &lt;label class="option" for="edit-datetime-worker-2"&gt;
                &lt;input type="radio" id="edit-datetime-worker-2" name="datetime_worker" value="2011-12-06T09:00:00::3"   class="form-radio" /&gt;
                &lt;span&gt;6. 12. 2011 – 09:00&lt;/span&gt;&lt;/label&gt;
                &lt;/div&gt;
            &lt;/td&gt;
            &lt;td&gt;&lt;div class="form-item" id="edit-datetime-worker-13-wrapper"&gt;
                &lt;label class="option" for="edit-datetime-worker-13"&gt;
                &lt;input type="radio" id="edit-datetime-worker-13" name="datetime_worker" value="2011-12-07T09:00:00::3"   class="form-radio" /&gt;
                &lt;span&gt;7. 12. 2011 – 09:00&lt;/span&gt;&lt;/label&gt;
                &lt;/div&gt;
            &lt;/td&gt;
        &lt;/tr&gt;
    &lt;/tbody&gt;
&lt;/table&gt;
</code></pre>

<p>From the previous step I have a number, say 2. So I check the first radio button in the second column (středa 7. 12. 2011) and I need to add a class to the cell below (or div in it).</p>

<p>How can I achieve this? I'm really a noob in JS. :(
If you need additional information, don't hesitate to ask.</p>
