We are learning higher-order functions in our class and our professor mentioned that they can be useful for web programming. I'm unsure as to what cases in which that would be true and was wondering if anyone had any experiences with higher-order functions in some common web programming tasks, and in what situations they would be useful.

I read through our book, but web programming wasn't mentioned, I suppose it was just something the professor mentioned off topic, but it sparked my interest a bit.

Thanks!