At the beginning of an article or webpage, a functions as a miniature version of the document, giving readers all the key points while skipping over details. this compositional mode can also function as a review, reminding readers of the key points they've just read. en2150

The answer is a summary function.  At the start of an article or web page, a summary functions as a small version of the document, giving readers all the key points while hopping over the other information. In some occurrences, this is all a reader needs. In other examples, the straightforward summary helps a reader choose whether to devote the time needed to read the full document. At the last part of an article or web page, a summary functions as a review, recapping readers of the key points they've just read.