Make Eww recognize additional types of URLs as next/previous

mark-next-previous.el

(defvar navigation-group-regex "postnav\\|navigation"
  "Regular expression to match the class of the navigation container")
(defvar prev-link-labels-regex "earlier\\|previous"
  "Regular expression matching the `previous` link")
(defvar next-link-labels-regex "later\\|next"
  "Regular expression matching the `next` link")

(defun my-eww-add-rel-prev-next ()
  "Add rel=\"prev\" and rel=\"next\" attributes to postnav links in EWW."
  (when (eq major-mode 'eww-mode)
    (let ((dom (plist-get eww-data :dom)))
      (when dom
        (let* ((nav (dom-by-class dom navigation-group-regex))
               (links (and nav (dom-by-tag nav 'a))))
          (when links
            (dolist (link links)
              (let ((text (string-trim (dom-text link))))
                (cond
                 ((string-match-p prev-link-labels-regex (downcase text))
                  (plist-put eww-data :previous (dom-attr link 'href)))
                 ((string-match-p next-link-labels-regex (downcase text))
                  (plist-put eww-data :next (dom-attr link 'href)))))))
          ;; No re-render needed — DOM is updated in place
          (plist-put eww-data :dom dom))))))

(add-hook 'eww-after-render-hook #'my-eww-add-rel-prev-next)

To make this work with a particular website, make sure its specific structure can be properly matched by extending navigation-group-regex, prev-link-labels-regex, and next-link-labels-regex.

This is the result of an exploration I did, inspired by how Greasemonkey can run arbitrary scripts upon page load.