title: jQuery Chaining Country / State Selects with OptGroup
body: <p>I have the following 2 select lists.. I'd like to hide State/Prov until the chosen Country has a corresponding optgroup label. So.. </p>
  
  <p>--User Selects Alegeria.. No State select is shown..</p>
  
  <p>--User Selects United States or Canada; The State Selects appears showing only the values where optgroup label matches the parents name.</p>
  
  <p>Make Sense? Can't find a way to do it based on OptGroup vs. having to manually assign a 'class' to each child object</p>
  
  <pre><code>&lt;select id="C_Country" name="C_Country" aria-required="true" class="required"&gt;
      &lt;option value=" " selected=""&gt;-- Please Select --&lt;/option&gt;
      &lt;option value="AF"&gt;Afghanistan&lt;/option&gt;
      &lt;option value="AX"&gt;Aland Islands&lt;/option&gt;
      &lt;option value="USA"&gt;United States&lt;/option&gt;
      &lt;option value="DZ"&gt;Algeria&lt;/option&gt;
      &lt;option value="CA"&gt;Canada&lt;/option&gt;
      &lt;option value="AD"&gt;Andorra&lt;/option&gt;
  &lt;/select&gt;
  
  
  &lt;p&gt;&lt;label for="C_State_Prov"&gt;State or Province &lt;span title="required"&gt;*&lt;/span&gt;&lt;/label&gt;&lt;/p&gt;
  &lt;select id="C_State_Prov" name="C_State_Prov" aria-required="true" class="required"&gt;
      &lt;option value="" selected=""&gt;-- Please Select --&lt;/option&gt;
      &lt;optgroup label="United States"&gt;
      &lt;option value="AK"&gt;Alaska&lt;/option&gt;
      &lt;option value="AL"&gt;Alabama&lt;/option&gt;
      &lt;option value="AR"&gt;Arkansas&lt;/option&gt;
      &lt;option value="AZ"&gt;Arizona&lt;/option&gt;
      &lt;option value="CA"&gt;California&lt;/option&gt;
      &lt;/optgroup&gt;
      &lt;optgroup label="Canada"&gt;
      &lt;option value="AB"&gt;Alberta&lt;/option&gt;
      &lt;option value="BC"&gt;British Columbia&lt;/option&gt;
      &lt;option value="MB"&gt;Manitoba&lt;/option&gt;
      &lt;/optgroup&gt;
  &lt;/select&gt;
  </code></pre>