WordPress: Allow anchor target attribute in user biography field.

gistfile1.php

<?php

// Don't include the above

add_filter( 'wp_kses_allowed_html', 'georgef_allow_anchor_target_attribute_in_biography', 20, 2 );
/**
 * Allow links to have a target attribute in user biographical information.
 *
 * @author Gary Jones
 * @link   http://www.studiopress.com/forums/topic/about-the-author-box-can-open-links-in-new-window/
 *
 * @param  array  $tags    Multi-dimensional array of allowed elements and their attributes.
 * @param  string $context Context under which wp_kses is operating.
 *
 * @return array          Amended allowed elements and attributes.
 */
function prefix_allow_anchor_target_attribute_in_biography( $tags, $context ) {
	if ( ! in_array( $context, array( 'pre_user_description', 'user_description' ) ) )
		return $tags;
	$tags['a']['target'] = true;
	return $tags;
}