ScrollLocker

Lock and unlock page scrolling

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/589163/1889704/ScrollLocker.js

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Wrap lines

// ==UserScript==
// @name         ScrollLocker
// @name:zh-CN   ScrollLocker
// @namespace    https://greasyfork.org/zh-CN/users/1570630
// @version      1.2
// @description  Lock and unlock page scrolling
// @description:zh-CN 锁定与恢复页面滚动
// @author       ryxel
// @license      MIT
// ==/UserScript==

var scrollLocker = (function() {
  'use strict';

  if (!document.__scrollLockerData) {
    document.__scrollLockerData = {
      lockCount: 0,
      savedStyle: null,
      isMobile: null
    };
  }

  const data = document.__scrollLockerData;

  const locker = {
    isLocked: false,

    lock() {
      if (locker.isLocked) return;
      locker.isLocked = true;

      if (++data.lockCount > 1) return;

      if (data.isMobile === null) data.isMobile = /Android|iPhone|iPad|iPod|Mobile/i.test(navigator.userAgent);

      data.savedStyle = {
        bodyOverflow: document.body.style.overflow,
        bodyPaddingRight: document.body.style.paddingRight,
        htmlOverflow: document.documentElement.style.overflow
      };

      if (data.isMobile) {
        document.body.style.overflow = 'hidden';
        document.documentElement.style.overflow = 'hidden';
      } else {
        const oldWidth = document.body.clientWidth;
        const oldPaddingRight = parseFloat(window.getComputedStyle(document.body).paddingRight) || 0;

        document.body.style.overflow = 'hidden';
        document.documentElement.style.overflow = 'hidden';

        const diff = document.body.clientWidth - oldWidth;
        if (diff > 0) document.body.style.paddingRight = `${oldPaddingRight + diff}px`;
      }
    },

    unlock() {
      if (!locker.isLocked) return;
      locker.isLocked = false;

      if (data.lockCount <= 0) return;

      if (--data.lockCount > 0) return;

      document.body.style.overflow = data.savedStyle.bodyOverflow;
      document.body.style.paddingRight = data.savedStyle.bodyPaddingRight;
      document.documentElement.style.overflow = data.savedStyle.htmlOverflow;

      data.savedStyle = null;
    }
  };

  return locker;
})();