Google handbag dave

My toll house cookies came out of the oven fine then went flat. WHY? - how can fine cookies from megaupload

I have all the same ingredients that I used for 40 years. I am fresh soda, 2 soft stick of butter fresh, 2 eggs and all the ingredients and steps as it is written on the envelope. When she left the stove looked good. Then flat! Ewwwww ... WHY!