Download textbooks from the smartedu.cn (tested in Google Chrome browser).

Notes:

1. If you have granted pop-up permission to the smartedu.cn domain, and cannot load books when using this script now, please reset (cancel) the pop-up permission.
2. Since the book is loading slowly, it's possible that the script doesn't work. Please try multiple times (1) wait the book finishing loading, then refresh the page, and (2) close the tab and reopen it.