code: function() {
  		if (insertCounter === 3) {
  			insertBtn.disabled = true;
  		}
  		else {
  			insertBtn.disabled = false;
  		}
  		
  		if (insertCounter === -3) {
  			removeBtn.disabled = true;
  		}
  		else {
  			removeBtn.disabled = false;
  		}
  	}
docs: Insert, Update, Remove