Firefox Hide Scrollbars

Hide Scrollbars in Firefox
目前為 2018-06-14 提交的版本，檢視最新版本。
安裝腳本 ?
Wrap lines
// ==UserScript==
// @name         Firefox Hide Scrollbars
// @namespace    http://qashto.com/
// @version      2.1.0
// @description  Hide Scrollbars in Firefox
// @author       qashto
// @match        *://*/*
// @exclude      *://www.youtube.com/*
// @run-at       document-start
// @grant        GM_addStyle
// ==/UserScript==

console.log('hiding scrollbars...');

// if used as userscript add style with GM_addStyle
if (typeof GM_addStyle !== 'undefined') {
  GM_addStyle(`
    :root {
      --scrollbar-height: 0;
      --scrollbar-width: 0;
      height: 100vh !important;
      overflow: hidden !important;
      position: relative !important;
      width: 100vw !important;
    }

    :root,
    body {
      max-height: initial !important;
      max-width: initial !important;
      min-height: initial !important;
      min-width: initial !important;
      position: relative;
    }

    body {
      height: calc(100vh + var(--scrollbar-height)) !important;
      overflow: auto !important;
      width: calc(100vw + var(--scrollbar-width)) !important;
    }
  `);
}

/**
 * Compatibility with userscripts. Userscripts run in a different context to
 * content scripts and don't need to make structured clones to pass objects
 * to page scripts.
 */
if (!exportFunction && !cloneInto) {
  function exportFunction(func, targetScope, options = {}) {
    if (options.defineAs) {
      targetScope[options.defineAs] = func;
    }

    return func;
  }

  function cloneInto(obj) {
    return obj;
  }

  window.wrappedJSObject = window;


  // Userscript-specific definition of document getters/setters
  let documentScrollHandler;
  Object.defineProperties(Document.prototype, {
    scrollingElement: {
      get() {
        return document.body;
      }
    },
    onscroll: {
      get() {
        return documentScrollHandler;
      },
      set(listener) {
        if (documentScrollHandler) {
          document.body.removeEventListener("scroll", documentScrollHandler);
        }
        if (listener) {
          documentScrollHandler = listener;
          document.body.addEventListener('scroll', documentScrollHandler);
        }
      }
    }
  });
} else if (browser && browser.runtime && browser.runtime.id) {
  /**
   * getters/setters cannot be passed via structured clone, so we have to inject
   * a script into the page context.
   */
  const scriptElement = document.createElement("script");
  scriptElement.src = browser.runtime.getURL("js/pageContext.js");
  scriptElement.addEventListener("load", () => {
    scriptElement.remove();
  });

  document.documentElement.appendChild(scriptElement);
}

function getScrollbarSize() {
  const div = document.createElement('div');
  div.style.visibility = 'hidden';
  div.style.overflow = 'scroll';
  document.documentElement.appendChild(div);

  const scrollbarHeight = div.offsetHeight - div.clientHeight;
  const scrollbarWidth = div.offsetWidth - div.clientWidth;

  div.remove();

  return [
    scrollbarWidth,
    scrollbarHeight
  ];
}

document.addEventListener('DOMContentLoaded', () => {
  const [scrollbarWidth, scrollbarHeight] = getScrollbarSize();

  document.body.style.setProperty(
    '--scrollbar-height', `${scrollbarHeight}px`);
  document.body.style.setProperty(
    '--scrollbar-width', `${scrollbarWidth}px`);


  document.body.addEventListener('scroll', ev => {
    const scrollLeft = cloneInto(document.body.scrollLeft, window);
    const scrollTop = cloneInto(document.body.scrollTop, window);

    window.wrappedJSObject.scrollX = scrollLeft;
    window.wrappedJSObject.pageXOffset = scrollLeft;
    window.wrappedJSObject.scrollY = scrollTop;
    window.wrappedJSObject.pageYOffset = scrollTop;
  });

  exportFunction(document.body.scroll.bind(document.body), window, {
    defineAs: 'scroll'
  });
  exportFunction(document.body.scrollTo.bind(document.body), window, {
    defineAs: 'scrollTo'
  });
  exportFunction(document.body.scrollBy.bind(document.body), window, {
    defineAs: 'scrollBy'
  });
});

function handleAddScrollEvent() {
  if (arguments[0] === 'scroll') {
    document.body.addEventListener(...arguments);
    return;
  }
}

function handleRemoveScrollEvent() {
  if (arguments[0] === 'scroll') {
    document.body.removeEventListener(...arguments);
    return;
  }
}


const initial_windowAddEventListener = Window.prototype.addEventListener;
const initial_windowRemoveEventListener = Window.prototype.removeEventListener;
const initial_documentAddEventListener = Document.prototype.addEventListener;
const initial_documentRemoveEventListener = Document.prototype.removeEventListener;

function windowAddEventListener() {
  handleAddScrollEvent(...arguments);
  initial_windowAddEventListener.apply(this, arguments);
}

function windowRemoveEventListener() {
  handleRemoveScrollEvent(...arguments);
  initial_windowRemoveEventListener.apply(this, arguments);
}

function documentAddEventListener() {
  handleAddScrollEvent(...arguments);
  initial_documentAddEventListener.apply(this, arguments);
}

function documentRemoveEventListener() {
  handleRemoveScrollEvent(...arguments);
  initial_documentRemoveEventListener.apply(this, arguments);
}

exportFunction(windowAddEventListener, Window.prototype, {
  defineAs: 'addEventListener'
});
exportFunction(windowRemoveEventListener, Window.prototype, {
  defineAs: 'removeEventListener'
});
exportFunction(documentAddEventListener, Document.prototype, {
  defineAs: 'addEventListener'
});
exportFunction(documentRemoveEventListener, Document.prototype, {
  defineAs: 'removeEventListener'
});

console.log('scrollbars hidden!');