GuiText Score On Mouse Click

Hello, Im trying to make a scoring system in two parts, one that is attached to a GUIText and another that is attached to an object to be clicked in order to add up points.

This is what I currently have on the GUIText

 var Counter : int = 0;
 
 function onGUI(){
     guiText.text = "Score: "+CountingCode.score;
 }

and this is what is on the object to be clicked to get points

CountingCode.js

 static var Counter : int = 0;
 
 function OnMouseDown(){
       Counter+=10;
 }

When I click the afformentioned object with these scripts active nothing happens. Can someone please show me what is wrong?