I need help with Javascript

I have a script
but the script is for when I walk over to my gun and the gui pops up, how do i get rid of the gui by either pressing 2 or walking away


var message = false;

function OnTriggerEnter (other : Collider) {

message = true; }

function OnGUI () {
if (message){
  GUI.Box (Rect (600, 350, 250, 40), "Press 2 to take this gun");
  }
  }

You could use the OnTriggerExit function and use a var for input;

private var message = false;
private var gunTaken = false;  //A variable for if you have taken the gun

function OnTriggerEnter(other : Collider){ 
message = true; 
}

function OnTriggerExit(other : Collider){  //if we exit the collider we cant pick it up
message = false;
}

function OnGUI () {
     if (message && !gunTaken){  //if you haven't taken the gun
     GUI.Box (Rect (600, 350, 250, 40), "Press 2 to take this gun");
          if(Input.GetKeyDown(KeyCode.2){  //if you take the gun it is taken
          gunTaken = true;
          }
     }
}

OnTriggerExit, set message to false.

var message = false;
 
function OnTriggerEnter (other : Collider) {
	if (!message){
		message = true; 
	}
}

function OnTriggerExit (other : Collider) {
	if (message){
		message = false;
	}
}

function OnGUI () {
	if (message){
		GUI.Box (Rect (600, 350, 250, 40), "Press 2 to take this gun");
	}
}