HTML: Select all

<select name='press_archive' onChange='document.parchived.submit();'>
            <option value='yes' class='pending' selected>Yes</option>
            <option value='no' class='approved'>No</option>
        </select>

The above code displays the class formatting correctly in IE6. (ie. Yes is shown in green text, No in red text).

In Firefox (latest version), it doesnt display any formatting. However if you select the option, the other items in the drop down list will be correctly formatted.

Any ideas how to fix this?