Question

        if($('.navigation ul li ul').children().length === 1) {
            $('.navigation ul li ul li a').css({opacity:0.5});
        }
        else {
            $('.navigation ul li ul li:first-child a').addClass('first');
            $('.navigation ul li ul li:last-child a').addClass('last');
        }

Basically I want it so if the navigation has one <li> for it to do something else than if it has more than 1 <li> in the unordered list.

SAMPLE HTML:

<nav id="nav" class="navigation"><!--Start Navigation-->          
    <ul> 
        <li><a href="#">Sample Linkk</a>
            <ul>
                <li><a href="#">1 DropDown Item</a></li>
            </ul>
        </li>
        <li><a href="#">Sample Link 2</a>
            <ul>
                <li><a href="#">2 DropDown Items</a></li>
                <li><a href="#">2 DropDown Items</a></li>
            </ul>
        </li>
    </ul>
 </nav>

Answer 1

$('.navigation ul li ul').each(function(){
   if($(this).children().length === 1){
      $(this).find('a').css({opacity:0.5});
   }else{
      $('li:first a', $(this)).addClass('first');
      $('li:last a', $(this)).addClass('last');
   }
});

Not tested it but I think it will work