Scripting Reference
Component.GetComponentInChildren

function GetComponentInChildren (t : Type) : Component

Description

Returns the component of Type type in the GameObject or any of its children using depth first search.

Only active components are returned.

JavaScript 
    var script : ScriptName; 
    script = GetComponentInChildren(ScriptName);
    script.DoSomething ();
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public ScriptName script;
    void Example() {
        script = GetComponentInChildren<ScriptName>();
        script.DoSomething();
    }
}
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public script as ScriptName

    def Example():
        script = GetComponentInChildren[of ScriptName]()
        script.DoSomething()

function GetComponentInChildren.<T> () : T

Description