gistfile1.txt

<label>Department:</label> 
<select id="blog_department_id" name="blog[department_id]">
<option value="1" selected="selected">My World</option>
<option value="2">Around Town</option>
<option value="3">Lifestyles &amp; Living</option>
<option value="4">Arts &amp; Entertainment</option>
<option value="5">Style &amp; Fashion</option>
<option value="6">Sports &amp; Fitness</option>
<option value="7">Business &amp; Careers</option>
<option value="8">Science &amp; Technology</option>
<option value="9">Society &amp; World</option>
<option value="10">Travel &amp; Leisure</option>
<option value="11">Offbeat &amp; WTF</option>
<option value="12">Random Thoughts</option>
</select>  	

<label>Channel:</label>
<select id="blog_channel_id" name="blog[channel_id]">
<option value="4-1">Music</option>
<option value="8-2">Open Source</option>
<option value="8-3">Closed Source</option>
<option value="4-4">Impressionisism</option></select>  	


<script type="text/javascript" charset="utf-8">
//<![CDATA[
jQuery(function($){
  // call on page load to start filter off correctly
  filterChannels($("#blog_department_id").val());
  
  // call anytime menu is changed
  $("#blog_department_id").change( function() { $('#blog_channel_id').options = filterChannels($(this).val()) } );
  
  function filterChannels(department_id) {
    $('#blog_channel_id option').filter(function() {
      return this.value.match(/^8/) != null;
    });
  }
});
//]]>
</script>