Scroll to Bottom and Top Button

Greasy Fork is available in English.
Scroll to Bottom and Top Button

Add buttons to scroll to the bottom and top of the website
换行
// ==UserScript==
// @name         Scroll to Bottom and Top Button
// @name:zh      底部和顶部按钮
// @namespace    http://greasyfork.icu/
// @version      1.1
// @description  Add buttons to scroll to the bottom and top of the website
// @description:zh 添加按钮以滚动到网页的底部和顶部
// @author       ghzxs
// @match        *://*/*
// @license      MIT
// @grant        none
// @run-at       document-end
// ==/UserScript==

(function() {
    'use strict';

    if (window !== window.top) {
        return;
    }

    function init() {
        if (!document.body) {
            // 如果document.body不存在，等待DOMContentLoaded事件
            window.addEventListener('DOMContentLoaded', init);
            return;
        }

        // Base64-encoded SVG data for bottom icon
        const base64BottomIcon = 'PHN2ZyBzdHJva2U9ImN1cnJlbnRDb2xvciIgZmlsbD0ibm9uZSIgc3Ryb2tlLXdpZHRoPSIyIiB2aWV3Qm94PSIwIDAgMjQgMjQiIHN0cm9rZS1saW5lY2FwPSJyb3VuZCIgc3Ryb2tlLWxpbmVqb2luPSJyb3VuZCIgY2xhc3M9Imljb24tc20gbS0xIiBoZWlnaHQ9IjFlbSIgd2lkdGg9IjFlbSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48bGluZSB4MT0iMTIiIHkxPSI1IiB4Mj0iMTIiIHkyPSIxOSI+PC9saW5lPjxwb2x5bGluZSBwb2ludHM9IjE5IDEyIDEyIDE5IDUgMTIiPjwvcG9seWxpbmU+PC9zdmc+';

        // Base64-encoded SVG data for top icon
        const base64TopIcon = 'PHN2ZyBzdHJva2U9ImN1cnJlbnRDb2xvciIgZmlsbD0ibm9uZSIgc3Ryb2tlLXdpZHRoPSIyIiB2aWV3Qm94PSIwIDAgMjQgMjQiIHN0cm9rZS1saW5lY2FwPSJyb3VuZCIgc3Ryb2tlLWxpbmVqb2luPSJyb3VuZCIgY2xhc3M9Imljb24tc20gbS0xIiBoZWlnaHQ9IjFlbSIgd2lkdGg9IjFlbSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48bGluZSB4MT0iMTIiIHkxPSIxOSIgeDI9IjEyIiB5Mj0iNSI+PC9saW5lPjxwb2x5bGluZSBwb2ludHM9IjUgMTIgMTIgNSAxOSAxMiI+PC9wb2x5bGluZT48L3N2Zz4=';

        // Common styles for both buttons
        const buttonStyles = {
            position: 'fixed',
            zIndex: '2',
            backgroundColor: 'none',
            border: '0.5px solid transparent',
            borderRadius: '50%',
            padding: '4px',
            cursor: 'pointer',
            display: 'flex',
            alignItems: 'center',
            justifyContent: 'center'
        };

        // Create the bottom button
        const bottomButton = document.createElement('button');
        const bottomImg = document.createElement('img');
        bottomImg.src = `data:image/svg+xml;base64,${base64BottomIcon}`;
        bottomImg.alt = 'Scroll to Bottom';
        bottomImg.style.width = '16px';
        bottomImg.style.height = '16px';
        bottomImg.style.display = 'block';
        bottomButton.appendChild(bottomImg);

        // Apply styles to the bottom button
        Object.assign(bottomButton.style, buttonStyles);
        bottomButton.style.bottom = '14px';
        bottomButton.style.right = '14px';

        // Add click event listener to scroll to the bottom
        bottomButton.addEventListener('click', function() {
            window.scrollTo({
                top: document.documentElement.scrollHeight || document.body.scrollHeight,
                behavior: 'smooth'
            });
        });

        // Create the top button
        const topButton = document.createElement('button');
        const topImg = document.createElement('img');
        topImg.src = `data:image/svg+xml;base64,${base64TopIcon}`;
        topImg.alt = 'Scroll to Top';
        topImg.style.width = '16px';
        topImg.style.height = '16px';
        topImg.style.display = 'block';
        topButton.appendChild(topImg);

        // Apply styles to the top button
        Object.assign(topButton.style, buttonStyles);
        topButton.style.bottom = '50px';
        topButton.style.right = '14px';

        // Add click event listener to scroll to the top
        topButton.addEventListener('click', function() {
            window.scrollTo({
                top: 0,
                behavior: 'smooth'
            });
        });

        // Append buttons to the body
        document.body.appendChild(bottomButton);
        document.body.appendChild(topButton);

        function throttle(func, delay) {
            let lastCall = 0;
            return function(...args) {
                const now = new Date().getTime();
                if (now - lastCall < delay) {
                    return;
                }
                lastCall = now;
                return func.apply(this, args);
            };
        }

        // Function to toggle the visibility of the top button
        function toggleTopButton() {
            if (window.scrollY === 0) {
                topButton.style.display = 'none';
            } else {
                topButton.style.display = 'flex';
            }
        }

        // Initial check
        toggleTopButton();

        window.addEventListener('scroll', throttle(toggleTopButton, 100));
    }

    // 初始化
    init();
})();