wp_ajax_get_tagcloud()

function wp_ajax_get_tagcloud() {
	if ( ! isset( $_POST['tax'] ) ) {
		wp_die( 0 );
	}

	$taxonomy = sanitize_key( $_POST['tax'] );
	$tax = get_taxonomy( $taxonomy );
	if ( ! $tax ) {
		wp_die( 0 );
	}

	if ( ! current_user_can( $tax->cap->assign_terms ) ) {
		wp_die( -1 );
	}

	$tags = get_terms( $taxonomy, array( 'number' => 45, 'orderby' => 'count', 'order' => 'DESC' ) );

	if ( empty( $tags ) )
		wp_die( $tax->labels->not_found );

	if ( is_wp_error( $tags ) )
		wp_die( $tags->get_error_message() );

	foreach ( $tags as $key => $tag ) {
		$tags[ $key ]->link = '#';
		$tags[ $key ]->id = $tag->term_id;
	}

	// We need raw tag names here, so don't filter the output
	$return = wp_generate_tag_cloud( $tags, array( 'filter' => 0, 'format' => 'list' ) );

	if ( empty($return) )
		wp_die( 0 );

	echo $return;

	wp_die();
}