Greasy Fork is available in English.
Shows all pages at once in online view for these sites: Asura Scans, Batoto, BilibiliComics, Comick, Dynasty-Scans, Flame Comics, Ikigai Mangas - EltaNews, Ikigai Mangas - Ajaco, KuManga, LHTranslation, Local Files, MangaBuddy, MangaDemon, MangaDex, MangaFox, MangaHere, Mangago, MangaHub, MangaKakalot, MangaNelo, MangaNato, MangaOni, Mangareader, MangaToons, ManhwaWeb, MangaGeko.com, MangaGeko.cc, ReadComicsOnline, ReaperScans, TuMangaOnline, WebNovel, WebToons, WeebCentral, Vortex Scans, ZeroSc
That is a very heavy feature, it would really slow down any browser if done by javascript, most likely would crash your browser every time. If this was an addon it would be possible but as script I believable its not feasible.
[Feature request] Download all chapters of a manga
Right now there is no option to download all chapters of a manga unless you manually go through, click on all the chapter links and click the download button. It would be great to be able to automatically spider through all the chapter links of a manga and download all the chapters in individual zip files that have 'readable' names (such as chapter one, chapter two, etc. being appended to the title of the manga) instead of MangaOnlineViewer.zip
Thanks,