MangaPlus Spacebar Navigation

mangaplus.js

// ==UserScript==
// @name         MangaPlus Spacebar Navigation
// @namespace    http://tampermonkey.net/
// @version      1.4
// @description  Use space/shift+space to simulate clicks for MangaPlus navigation.
// @author       You
// @match        https://mangaplus.shueisha.co.jp/viewer/*
// @grant        none
// ==/UserScript==

let lastMouseX = 0;
let lastMouseY = 0;

document.addEventListener('mousemove', (event) => {
  lastMouseX = event.clientX;
  lastMouseY = event.clientY;
});

document.addEventListener('keydown', (event) => {
  if (event.key === ' ') {
    event.preventDefault();
    event.stopPropagation();

    let x = lastMouseX;
    let y = lastMouseY;

    if (event.shiftKey) {
      // Flip horizontally across the viewport → simulate clicking on the other side
      x = window.innerWidth - lastMouseX;
    }

    const target = document.elementFromPoint(x, y);
    if (target) {
      const clickEvent = new MouseEvent('click', {
        bubbles: true,
        cancelable: true,
        view: window,
        clientX: x,
        clientY: y
      });
      target.dispatchEvent(clickEvent);
    }
  }
}, true);

actually... this works better. the problem is that body is blocking the real scroll container

// ==UserScript==
// @name         Universal Scroll Blocker + Fallback Scroll
// @namespace    http://tampermonkey.net/
// @version      1.3
// @description  Blocks hijacked scroll and restores PageUp/PageDown/Space on real scroll container.
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function getScrollTarget() {
        // try to find the actual scrollable element
        const candidates = document.querySelectorAll('*');
        for (const el of candidates) {
            const style = getComputedStyle(el);
            if (/(auto|scroll)/.test(style.overflowY) && el.scrollHeight > el.clientHeight) {
                return el;
            }
        }
        return document.scrollingElement || document.body;
    }

    window.addEventListener('keydown', (e) => {
        const target = e.target;
        if (['TEXTAREA', 'INPUT', 'SELECT'].includes(target.tagName) || target.isContentEditable) {
            return;
        }

        const scrollEl = getScrollTarget();
        const step = scrollEl.clientHeight * 0.9; // almost a page

        switch (e.code) {
            case 'Space':
            case 'PageDown':
                e.stopImmediatePropagation();
                e.preventDefault();
                scrollEl.scrollBy({ top: step, behavior: 'smooth' });
                break;
            case 'PageUp':
                e.stopImmediatePropagation();
                e.preventDefault();
                scrollEl.scrollBy({ top: -step, behavior: 'smooth' });
                break;
            case 'ArrowDown':
                e.stopImmediatePropagation();
                e.preventDefault();
                scrollEl.scrollBy({ top: 40, behavior: 'smooth' });
                break;
            case 'ArrowUp':
                e.stopImmediatePropagation();
                e.preventDefault();
                scrollEl.scrollBy({ top: -40, behavior: 'smooth' });
                break;
        }
    }, { capture: true });

    window.addEventListener('wheel', (e) => {
        e.stopImmediatePropagation();
    }, { capture: true, passive: false });

})();