You clicked on an indicator that there was a gap at that point in the material taken from the printed book.

Remember you were reading only a small sample from the book.

The book has lots of other interesting, amusing, and/or informative material about topics not touched on in these Web pages, besides what was omitted at the point where you clicked. If you would like to know more about these fascinating writing systems and the people that use them, John Benjamins will be happy to sell you a copy.