WordPress/wp-admin/edit-category-form.php

<?php
/**
 * Edit category form for inclusion in administration panels.
 *
 * @package WordPress
 * @subpackage Administration
 */

/**
 * @var object
 */
if ( ! isset( $category ) )
	$category = (object) array();

if ( ! empty($cat_ID) ) {
	/**
	 * @var string
	 */
	$heading = '';
	$submit_text = __('Edit Category');
	$form = '<form name="editcat" id="editcat" method="post" action="categories.php" class="validate">';
	$action = 'editedcat';
	$nonce_action = 'update-category_' . $cat_ID;
	do_action('edit_category_form_pre', $category);
} else {
	$heading = '<h2>' . __('Add Category') . '</h2>';
	$submit_text = __('Add Category');
	$form = '<form name="addcat" id="addcat" method="post" action="categories.php" class="add:the-list: validate">';
	$action = 'addcat';
	$nonce_action = 'add-category';
	do_action('add_category_form_pre', $category);
}

/**
 * @ignore
 * @since 2.7
 * @internal Used to prevent errors in page when no category is being edited.
 *
 * @param object $category
 */
function _fill_empty_category(&$category) {
	if ( ! isset( $category->name ) )
		$category->name = '';

	if ( ! isset( $category->slug ) )
		$category->slug = '';

	if ( ! isset( $category->parent ) )
		$category->parent = '';

	if ( ! isset( $category->description ) )
		$category->description = '';
}

_fill_empty_category($category);
?>

<div class="wrap">
<?php echo $heading ?>
<div id="ajax-response"></div>
<?php echo $form ?>
<input type="hidden" name="action" value="<?php echo $action ?>" />
<input type="hidden" name="cat_ID" value="<?php echo $category->term_id ?>" />
<?php wp_nonce_field($nonce_action); ?>
	<table class="form-table">
		<tr class="form-field form-required">
			<th scope="row" valign="top"><label for="cat_name"><?php _e('Category Name') ?></label></th>
			<td><input name="cat_name" id="cat_name" type="text" value="<?php echo attribute_escape($category->name); ?>" size="40" aria-required="true" /><br />
            <?php _e('The name is used to identify the category almost everywhere, for example under the post or in the category widget.'); ?></td>
		</tr>
		<tr class="form-field">
			<th scope="row" valign="top"><label for="category_nicename"><?php _e('Category Slug') ?></label></th>
			<td><input name="category_nicename" id="category_nicename" type="text" value="<?php echo attribute_escape(apply_filters('editable_slug', $category->slug)); ?>" size="40" /><br />
            <?php _e('The &#8220;slug&#8221; is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.'); ?></td>
		</tr>
		<tr class="form-field">
			<th scope="row" valign="top"><label for="category_parent"><?php _e('Category Parent') ?></label></th>
			<td>
	  			<?php wp_dropdown_categories(array('hide_empty' => 0, 'name' => 'category_parent', 'orderby' => 'name', 'selected' => $category->parent, 'hierarchical' => true, 'show_option_none' => __('None'))); ?><br />
                <?php _e('Categories, unlike tags, can have a hierarchy. You might have a Jazz category, and under that have children categories for Bebop and Big Band. Totally optional.'); ?>
	  		</td>
		</tr>
		<tr class="form-field">
			<th scope="row" valign="top"><label for="category_description"><?php _e('Description') ?></label></th>
			<td><textarea name="category_description" id="category_description" rows="5" cols="50" style="width: 97%;"><?php echo wp_specialchars($category->description); ?></textarea><br />
            <?php _e('The description is not prominent by default, however some themes may show it.'); ?></td>
		</tr>
	</table>
<p class="submit"><input type="submit" class="button" name="submit" value="<?php echo $submit_text ?>" /></p>
<?php do_action('edit_category_form', $category); ?>
</form>
</div>