Descriptions on Header Menu

functions.php

<?php

/**
 * Descriptions on Header Menu
 * @author Bill Erickson
 * @link http://www.billerickson.net/code/add-description-to-wordpress-menu-items/
 * 
 * @param string $item_output, HTML outputp for the menu item
 * @param object $item, menu item object
 * @param int $depth, depth in menu structure
 * @param object $args, arguments passed to wp_nav_menu()
 * @return string $item_output
 */
function be_header_menu_desc( $item_output, $item, $depth, $args ) {
	
	if( 'header' == $args->theme_location && ! $depth && $item->description )
		$item_output = str_replace( '</a>', '<span class="description">' . $item->description . '</span></a>', $item_output );
		
	return $item_output;
}
add_filter( 'walker_nav_menu_start_el', 'be_header_menu_desc', 10, 4 );

@param string $item_output, HTML outputp for the menu item clerical mistake outputp.

I adjusted the function a little bit:

function be_header_menu_desc( $item_output, $item, $depth, $args ) {
    if( ! 'header' == $args->theme_location && $depth && ! $item->description ) return $item_output;
    $item_output = str_replace( '</a>', sprintf( '<span class="description">%s</span></a>', $item->description ), $item_output );
    return $item_output;
}
add_filter( 'walker_nav_menu_start_el', 'be_header_menu_desc', 10, 4 );

Hello,
Is there a way to make this work with putting the description in front of the <a href>?

@oneblackcrayon, yes
$item_output .= "<span>$item->description</span>";
and add styles to span.