[jQuery] Get element by class based on document.location variable

[PaulC]

I have a set of lists with child elements – these are my navigation.
Each top level list item a has a class that corresponds to a given
section.

The child elements are hidden by default. I want a correct child list
to open based on the URL you are visiting.

The code I have is as follows:

var currentSection = document.location.toString().split('/')[4];

I then want the list item with the matching class to the var
currentSection to slide open. I thought it was this:
$("." + currentSection).slideDown(500);

But it doesn’t work!