Creating a book reading widget, how to split text in two pages automatically

Hi, I would like to make a book reading widget in my game. The problem I have is how to split the text between two pages (and then subsequent pages) considering the text is coming from the server, and can have varying length based on the book you are reading. I need to know from the TextBox when its clipping the text , so I can split the text in the next page. I have two textboxes, one for the left page, one for the right page, and I need to split the text between the two. Any idea on how to do so?