How Would I Make A GUI Label Fade After A Certain Amount Of Time?

Hi, I'm trying to make a GUI Label fade out after a certain amount of time and I need some help on how to do it, preferably in JavaScript.

Some javascript:

var color : Color;

function Start()
{
    color = Color.white;
    yield FadeOutAfterTime(3);
}

function OnGUI()
{
    GUI.color = color;
    GUILayout.Label("Hai!");
    // You probably want to restore GUI.Color here
}

function FadeOutAfterTime(time : float)
{
    yield WaitForSeconds(time);
    yield Fade();
}

function Fade()
{
   while (color.a > 0)
   { 
       color.a -= Time.deltaTime;
       yield;
   }
}