function Update () {
// To access public variables and functions
// in another script attached to the same game object.
// (ScriptName is the name of the javascript file)
var other : ScriptName;
other = gameObject.GetComponent("ScriptName");
// Call the function DoSomething on the script
other.DoSomething ();
// set another variable in the other script instance
other.someVariable = 5;
}

function Update () {
var other : ScriptName;
other = gameObject.GetComponent("ScriptName");
other.someVariable = 5;
}