title: both of the radio buttons can be selected
body: <p>I have form with 2 radio buttons but both of the radio buttons can be selected, </p>
  
  <pre><code>     &lt;form class="descriptions" id="collection"  method="post" action=""&gt;
                            &lt;table width="200"&gt;
                                &lt;tr&gt;
                                  &lt;td&gt;
                                    &lt;label&gt;Collection&lt;/label&gt;
                                    &lt;input type="radio" value="collection" /&gt;
                                  &lt;/td&gt;
                                  &lt;td&gt;
                                    &lt;label&gt;Delivery&lt;/label&gt;
                                    &lt;input type="radio" value="delivery"    /&gt;
                                  &lt;/td&gt;  
                              &lt;/tr&gt;
                           &lt;/table&gt;
  
                  &lt;/form&gt;
  </code></pre>
  
  <p>I know this is very easy but I can't seem to find the answer, 
  any help would be appreciated.</p>