Javascript GetComponent not work!

Hi,

I have a tow scripts:

 stage.js
 net.js

i need include net.js on stage.js, I found this code :

 stage.js : 
 function Start () 
 {
     var net : net;
     net = GetComponent("net");
     net.hello();
 }
 
 net.js :
 public function hello() : int
 {
     Debug.Log("Hello World");
     return 1;
 }

but in not work , Error :

 NullReferenceException: Object reference not set to an instance of an object
 stage.Start () 

I wrote in C#, did not matter, not work!

 C# Error!
 
     using UnityEngine;
     using System.Collections;
     
     public class Stage : MonoBehaviour
     {
     
         private Net net;
     
         // Initialization
         void Start () {
             net = GetComponent<Net> ();
             net.hello();
         }
     
     
         // Update
         void Update () {
         }
     }
 
 
     using UnityEngine;
     using System.Collections;
     
     public class Net : MonoBehaviour {
     
          void hello(){
             Debug.Log("Hello");
         }
     }
     
 

Why? help me please. thank you.