To be able to take advantage of the particular jQuery menu in WordPress, I want the kid UL (dropdown area of the menu) to possess a selector put into it (third line, below):

<ul class="dropdown">
    <li>the first list item
        <ul class="sub_nav">
            <li>child list item</li>

Note: I omitted the hyperlink code for greater clearness.

I am not really a coder. My PHP and javascript abilities are from the copy-paste-mess variety. Other forums have produced plenty of vague suggestions, but no solutions. I am available to other solutions, but Let me solve it in 1 of 2 places:

  1. Modify <#?php wordpress_list_pages('title_li=&depth=2') ?> within the theme header.php file
    [needed to add # to code bit to really make it appear]

  2. Give a function within the theme functions.php file

Mike Little of furnished an answer on the LinkedIn forum:

Within the theme functions file:

class My_Master_Page stretches Master_Page amplifier$output, $depth)

Within the header file where menu would be to appear:

<ul class="dropdown"><?php $master = new My_Master_Page
wordpress_list_pages(array('title_li'=>'', 'depth' => 2, 'walker' => $master)) ?></ul>

Mucho gracias to Mike Little, who had been a founding person in the WordPress team.

To include a category towards the <ul> you should use jQuery, however i think it can be done without adding a category towards the second ul.

To include class jQuery('ul.dropdown li ul').addClass('sub_nav');

you can now use jQuery('ul.sub_nav') for anything you requirement for, nevertheless its just like jQuery('ul.dropdown li ul') therefore it will not make a difference either you add class or otherwise.