Adding Fields to the Category, Tag and Custom Taxonomy Edit Screen in the WordPress Admin?

The question is “How do I add one or more fields to the Category, Tag and Custom Taxonomy Edit Screen in the WordPress Admin?” This question was asked on the wp-hackers list August 1st 2010 and I offered a solution later that day. The original asker discussed the issue again today (Aug 21) which reminded me of the solution. Since it could be a common need I decided to post the solution including code up here for others to find in the future.

I added new field ‘picture’ (input type file) to category with help of these

add_action('category_edit_form_fields','category_edit_form_fields');
add_action('category_edit_form', 'category_edit_form');
add_action('category_add_form_fields','category_edit_form_fields');
add_action('category_add_form','category_edit_form');


function category_edit_form() {
?>
<script type="text/javascript">
jQuery(document).ready(function(){
jQuery('#edittag').attr( "enctype", "multipart/form-data" ).attr( "encoding", "multipart/form-data" );
        });
</script>
<?php 
}

function category_edit_form_fields () {
?>
    <tr class="form-field">
            <th valign="top" scope="row">
                <label for="catpic"><?php _e('Picture of the category', ''); ?></label>
            </th>
            <td>
                <input type="file" id="catpic" name="catpic"/>
            </td>
        </tr>
        <?php 
    }

You are free to use any taxonomy, just replace category to your taxonomy name