CSS last-child(-1)

I am looking for a css selector that lets me select the pre-last child of list.

<ul>
     <li>1</li>
     <li>2</li>
     <li>3</li>
     <li>4</li>
     <li>5</li> <!-- select the pre last item dynamically no matter how long this list is -->
     <li>6</li>
</ul>

Static method:

ul li:nth-child(5)

Dynamic method:

ul li:last-child(-1)

which of course doesn't validate, also nth-last-child doesn't seem to provide a dynamic way.. I can fallback to javascript but I'm wondering if there is a css way I overlooked

You can use :nth-last-child(); in fact, besides :nth-last-of-type() I don't know what else you could use. I'm not sure what you mean by "dynamic", but if you mean whether the style applies to the new second last child when more children are added to the list, yes it will. Interactive fiddle.

ul li:nth-last-child(2)

Unless you can get PHP to label that element with a class you are better to use jQuery.

jQuery(document).ready(function () {
  $count =  jQuery("ul li").size() - 1;
  alert($count);
  jQuery("ul li:nth-child("+$count+")").css("color","red");
});