The one relevant example I can find ("jitter-gui-sliderexample") demonstrates their use in patcher objects, but not in a script.
First of all, I assume it's necessary to copy 'jitter_gui_slider.js' to the jsextensions folder, right?
After I've done that, at least I can add this line to my script and compile without error:
my_slider = new JitterGUISlider("holiday");
But that's as far as I can get.
If I try:
for(var n in my_slider)
I get back 'maxobj' and that's it - whereas with any actual max or jitter object I would get a full list of attributes (as properties of the object).
Of course if I add
my_slider.color = [0.8,0.4,0,1];
my_slider.position = [0,0,0];
my_slider.scale = [0.3,1,1];
I get those back as properties, but clearly they weren't there until I mentioned them.
(I'm assuming based on the example that color, position and scale are attributes of a JitterGUISlider - ?)