Ajax handler for deleting a tag.

function wp_ajax_delete_tag() {
	$tag_id = (int) $_POST['tag_ID'];
	check_ajax_referer( "delete-tag_$tag_id" );

	if ( ! current_user_can( 'delete_term', $tag_id ) ) {
		wp_die( -1 );
	}

	$taxonomy = ! empty( $_POST['taxonomy'] ) ? $_POST['taxonomy'] : 'post_tag';
	$tag      = get_term( $tag_id, $taxonomy );

	if ( ! $tag || is_wp_error( $tag ) ) {
		wp_die( 1 );
	}

	if ( wp_delete_term( $tag_id, $taxonomy ) ) {
		wp_die( 1 );
	} else {
		wp_die( 0 );
	}
}