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为网页添加平滑返回顶部按钮

当前为 2025-10-31 提交的版本,查看 最新版本

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Greasemonkey 油猴子Violentmonkey 暴力猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Violentmonkey 暴力猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Userscripts ,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name         Back to Top
// @namespace    http://tampermonkey.net/
// @version      0.9
// @description  为网页添加平滑返回顶部按钮
// @author       sept
// @match        *://*/*
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_registerMenuCommand
// @license      MIT
// @icon         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
// ==/UserScript==

(function () {
    'use strict';

    if (window.self !== window.top || window.myBackToTopScriptHasRun) {
        return;
    }
    window.myBackToTopScriptHasRun = true;

    const HOSTNAME = window.location.hostname;
    const ENABLED_SITES_KEY = 'back-to-top-enabled-sites';
    const BUTTON_POSITION_KEY = `back-to-top-button-position_${HOSTNAME}`;

    // 获取已启用的网站列表,默认为 a list of 'github.com'
    let enabledSites = GM_getValue(ENABLED_SITES_KEY, ['github.com']);

    // 检查当前网站是否已启用
    function isSiteEnabled() {
        return enabledSites.includes(HOSTNAME);
    }

    // 切换当前网站的启用状态
    function toggleSite() {
        if (isSiteEnabled()) {
            enabledSites = enabledSites.filter(site => site !== HOSTNAME);
        } else {
            enabledSites.push(HOSTNAME);
        }
        GM_setValue(ENABLED_SITES_KEY, enabledSites);
        window.location.reload();
    }

    // 注册菜单命令
    GM_registerMenuCommand(`${isSiteEnabled() ? '关闭' : '开启'}返回顶部`, toggleSite);

    // 如果当前网站未启用,则不执行任何操作
    if (!isSiteEnabled()) {
        return;
    }

    // 创建按钮元素
    const backToTopBtn = document.createElement('div');
    backToTopBtn.id = 'gemini-back-to-top-button';
    backToTopBtn.innerHTML = '↑';

    // 创建样式
    const style = document.createElement('style');
    style.textContent = `
        #gemini-back-to-top-button {
            position: fixed;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: linear-gradient(135deg, #238636, #2ea043);
            color: white;
            display: flex;
            justify-content: center;
            align-items: center;
            cursor: pointer;
            box-shadow: 0 4px 12px rgba(0,0,0,0.2);
            opacity: 0;
            transition: opacity 0.3s, transform 0.3s;
            font-size: 20px;
            font-weight: bold;
            z-index: 9999;
        }

        #gemini-back-to-top-button.visible {
            opacity: 1;
        }

        #gemini-back-to-top-button:hover {
            transform: scale(1.1);
            box-shadow: 0 6px 16px rgba(0,0,0,0.2);
        }

        #gemini-back-to-top-button:active {
            cursor: grabbing;
            transform: scale(0.9);
        }
    `;

    // 添加样式和按钮到页面
    document.head.appendChild(style);
    document.body.appendChild(backToTopBtn);

    function applyPosition(position) {
        let top, left;

        const buttonWidth = 40;
        const buttonHeight = 40;

        if (position.pctTop !== undefined && position.pctLeft !== undefined) {
            top = position.pctTop * (window.innerHeight - buttonHeight);
            left = position.pctLeft * (window.innerWidth - buttonWidth);
        } else if (position.top !== undefined && position.left !== undefined) {
            top = position.top;
            left = position.left;
        } else {
            return;
        }

        top = Math.max(0, Math.min(top, window.innerHeight - buttonHeight));
        left = Math.max(0, Math.min(left, window.innerWidth - buttonWidth));

        backToTopBtn.style.top = `${top}px`;
        backToTopBtn.style.left = `${left}px`;
    }

    const defaultPosition = { pctTop: 0.9, pctLeft: 0.9 };
    const savedPosition = GM_getValue(BUTTON_POSITION_KEY, defaultPosition);
    applyPosition(savedPosition);

    function smoothScrollTo(targetY, duration) {
        const startY = window.pageYOffset;
        const distance = targetY - startY;
        let startTime = null;

        function animation(currentTime) {
            if (startTime === null) startTime = currentTime;
            const timeElapsed = currentTime - startTime;
            const run = ease(timeElapsed, startY, distance, duration);
            window.scrollTo(0, run);
            if (timeElapsed < duration) requestAnimationFrame(animation);
        }

        // easeInOutQuad easing function
        function ease(t, b, c, d) {
            t /= d / 2;
            if (t < 1) return c / 2 * t * t + b;
            t--;
            return -c / 2 * (t * (t - 2) - 1) + b;
        }

        requestAnimationFrame(animation);
    }


    // 滚动事件监听
    window.addEventListener('scroll', function () {
        if (window.pageYOffset > 300) {
            backToTopBtn.classList.add('visible');
        } else {
            backToTopBtn.classList.remove('visible');
        }
    });

    // 窗口大小调整事件监听
    window.addEventListener('resize', () => {
        const pos = GM_getValue(BUTTON_POSITION_KEY, defaultPosition);
        applyPosition(pos);
    });

    let isDragging = false;
    let hasDragged = false;
    let offsetX, offsetY, startX, startY;

    backToTopBtn.addEventListener('mousedown', (e) => {
        isDragging = true;
        hasDragged = false;
        startX = e.clientX;
        startY = e.clientY;
        offsetX = e.clientX - backToTopBtn.getBoundingClientRect().left;
        offsetY = e.clientY - backToTopBtn.getBoundingClientRect().top;
        backToTopBtn.style.transition = 'none'; // Disable transition during drag
    });

    document.addEventListener('mousemove', (e) => {
        if (isDragging) {
            const dx = e.clientX - startX;
            const dy = e.clientY - startY;
            if (Math.sqrt(dx * dx + dy * dy) > 5) {
                hasDragged = true;
            }

            if (hasDragged) {
                let newTop = e.clientY - offsetY;
                let newLeft = e.clientX - offsetX;

                // Constrain to viewport
                newTop = Math.max(0, Math.min(newTop, window.innerHeight - backToTopBtn.offsetHeight));
                newLeft = Math.max(0, Math.min(newLeft, window.innerWidth - backToTopBtn.offsetWidth));

                backToTopBtn.style.top = `${newTop}px`;
                backToTopBtn.style.left = `${newLeft}px`;
            }
        }
    });

    document.addEventListener('mouseup', () => {
        if (isDragging) {
            isDragging = false;
            backToTopBtn.style.transition = 'opacity 0.3s, transform 0.3s'; // Re-enable transition
            if (hasDragged) {
                const pctTop = backToTopBtn.offsetTop / (window.innerHeight - backToTopBtn.offsetHeight);
                const pctLeft = backToTopBtn.offsetLeft / (window.innerWidth - backToTopBtn.offsetWidth);

                GM_setValue(BUTTON_POSITION_KEY, {
                    pctTop: Math.max(0, Math.min(1, pctTop)),
                    pctLeft: Math.max(0, Math.min(1, pctLeft)),
                });
            }
        }
    });

    // 点击事件 - 平滑滚动
    backToTopBtn.addEventListener('click', function () {
        if (!hasDragged) {
            smoothScrollTo(0, 300);
        }
    });
})();