Do teenage girls really wear clothes like that in school?

It has been nearly half a century since I was in high school but I thought the dress codes now are relatively strict in school. Are girls really allowed to wear very short skirts and to show substantial cleavage on campus during school? I am not surprised that they would be allowed to for special events, I am only asking about normal school hours. I think this movie exaggerated that part.

I am not being judgmental. As far as I am concerned, I am not trying to imply the dress code should be more permissive or less permissive, I am just asking if this movie exaggerated the truth.