http://imanas.shanghai.nyu.edu/~cl4690/w04-exercise-JS-Conditionals/index.html
This is really an interesting exercise. The most difficult part for me is the ruction part. At first, I don’t know how to get the other two pictures disappear, and professor Leon helped me with that and gave me a hint to use function to count the number of the click which helped me finally found it out. I was so happy when I figure the whole things out!!