Development has halted until I have more time. Pixiv uses async page loading, which broke some aspects of this script. Ultimate Pixiv Script: Direct Links, Auto-Paging, Preview, IQDB/Danbooru, Filter/Sort using Bookmark,views,rating,total score. | Safe Search | plus more. Works best with "Pixiv++ Manga Viewer" and "Generic Image Viewer". 自動ページング|ポケベル|ロード次ページ|フィルター|並べ替え|注文|ダイレクトリンク
< Feedback on [TS] Pixiv++ V3 alpha
xhr is only used for paging at the moment while GM_xhr is always used for api. There was a reason why I had to stick with only GM_xhr, and truth I can't recall the reason for it.
As to using iframe, that was the case because of a few issues with some browser (opera I think) not working with GM_xhr or xhr when page fetching. I had to use iframe to bypass it. I made it default iframe as I knew it will always work. Most users won't care or know and those that would can easily set the script setting using GM_setValue.
Once I get more time to work on it, I will clean the code and remove all redundant parts including trying to remove iframe and supporting xhr fully.
Default pageFetchingMethod to xmlHttpRequest
I would suggest using only xmlHttpRequest as the page fetching method and removing the others. Every current browser supports xhr, while GM_xhr is unnecessary, and iform is painfully slow and inefficient.