gui question

Could someone give a small example on how to make a simple gui horizontal slider. I can't get it to work. Here's what I tried:

Code (csharp):

1. var value = 1.0;
2. var minValue = 0.0;
3. var maxValue = 3.0;
4.  
5. function OnGUI ()
6. {
7.     GUI.HorizontalSlider (Rect (20, 20, 300, 30), value, minValue, maxValue);
8. }

Do I have to make the value variable equal to the mouse position, or something?

Thanks

 

There's actually a demo of an RGB slider in the compound components section of the Unity doco IIRC
cheers
Shaun

 

thanks