Help needed

[JesusFreak250]

hey I'm currently learning to script and I was on testbed just playing about trying to make a gralat script so that the player can make there gralats go up to 1000. It seems to work fine but after about 0.5 of a second the gralats go back to what i had before i used the weapon. I'm guessing it's something to do with it being clientside and it needs to be serverside but I'm not sure. So i need some help to make it work. I know its probably really bad but its one of my first attempt.

//#CLIENTSIDE
  
  function onKeyPressed(code, key, scancode) {
   
   if (key == "3") {
    
    player.rupees = 1000;
  }
 }