#9 JavaScript Game, Shop items purchasing problem, when i click it doesn't delete the text into it.

The problem is this: When i click on the buy item, it works yes but i doesn’t change the text, the headache is that function works only once time, when points is more than 20 points, but when i click on the shop, it generates again and again, and i don't know how to stop the text generation. But i think that i can solve it, please subscribe if you believe me :)