make scroll chat with scroll bar

here is my script it is javascript i am pretty sure it needs to be a array but i am not sure how to apply it to make my chat scroll

if you want to test it place the script on your camera

 var chats = 225;
 var chats1 = 190;
 
 var chatboxw = 10;
 var chatboxh = 235;
 var chatboxs = 195;
 var chatboxs1 = 145;
 
 var texth = 380;
 var texts = 25;
 
 var chattextw = 225;
 
 var enter : boolean = false;
 
 function OnGUI()
 {
     GUI.Box(Rect(chatw, chath, chats, chats1), chatbox);
     
     chat = GUI.TextField(Rect(chatboxw, chatboxh, chatboxs, chatboxs1), chattext);
     
     textbox = GUI.TextField(Rect(chatboxw, texth, chatboxs, texts), textbox);
     
     if(GUI.Button(Rect(chattextw, texth, 100, texts), "Enter"))
     {
         enter = !enter;
     }
         if (Input.GetKeyDown("return"))
     {
         enter = true;
     }
 }
 
 function Update ()
 {
         if(enter)
     {
         chattext = textbox;
         enter = false;
         textbox = "";
     }
 }