How can I make a gui with buttons pop up in javasript?

I am wanting to be able to hit “B” and a gui come up with buttons inside. Can someone help me in doing this?

#pragma strict
var buttonName :String;
private var act :boolean;
var closeOnButton :boolean; //Should it close again when you press b?
function Start () {

}

function Update () {
if(Input.GetKeyDown(buttonName)){
if(closeOnButton){
if(act){
act = false;
}else act = true;
}else{
act = true;
}
}
}

function OnGUI(){
if(act){
GUI.Box(Rect(Screen.width / 4, Screen.height / 4, Screen.width / 2, Screen.height / 2), ""); //Background Box
GUI.Button (Rect(Screen.width / 4 + 15, Screen.height / 4 + 15, Screen.width / 2 - 30, Screen.height / 4 - 15), "A Button here. 
Just add more if u want");
}
}