A jQuery plugin as requested by Andy Clarke (http://stuffandnonsense.co.uk, @Malarkey) to have effect as described in Andy Clarke's original blog post
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>
<script src="jquery.toggleOptionalFields.js" type="text/javascript"></script>
<script>
$(document).ready(function()
{
$("#example-form").toggleOptionalFields();
});
</script>
Update in line with comments on the original blog post this plugin has been updated to ensure it encompasses the spirit of progressive enhancement and below is a live example using Andy Clarke's original markup and css.