Q:

Insert class when slidetoggle is activated

Struggling with where to start on this one, apologies for not much code.
Using slide toggle to display a div when a is clicked. 
a currently has a background image with a defined position. I've created a sprite image, so that when the link is clicked, the background position will change to show a downwards pointing arrow (like a typical expanding list.)
How can I build into the function that when a is clicked, a class of arrowDown is added?
JS Fiddle
I'd like to add a class to this link:
<a>See opening times</a>

CSS needing to be added using classname arrowDown
a.arrowDown
{
    background-position: 2px -9px;
    }

Function:
$('.timeList a').click(function(e) {
    $(this).next().slideToggle('slow');
});

A:

You can use toggleClass method:
$('.timeList a').click(function(e) {
    $(this).toggleClass('arrowDown').next().slideToggle('slow');
});

