appear-on-scroll/demo/index.html at master · davemaynard/appear-on-scroll · GitHub

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<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>appear-on-scroll demo</title>
    <link rel="preconnect" href="https://fonts.googleapis.com" />
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
    <link
      href="https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500&family=IBM+Plex+Sans:ital,wght@0,400;0,500;0,600;1,500&display=swap"
      rel="stylesheet"
    />
    <style>
      :root {
        --bg: #0d1014;
        --surface: #14181e;
        --border: #222831;
        --text: #e8ebef;
        --muted: #8a929d;
        /* One accent for the whole page: warm, against a cool near-black. */
        --accent: #d9944a;
        /* Two radii, and only two: hairlines and cards. */
        --r-sm: 3px;
        --r: 8px;
        --nav-height: 64px;
        --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
      }

      * {
        box-sizing: border-box;
      }

      html {
        /* The scrollbar, form controls and overscroll all take the page's theme. */
        color-scheme: dark;
        background: var(--bg);
      }

      body {
        margin: 0;
        background: var(--bg);
        color: var(--text);
        font-family:
          'IBM Plex Sans',
          ui-sans-serif,
          system-ui,
          -apple-system,
          sans-serif;
        line-height: 1.6;
        -webkit-font-smoothing: antialiased;
      }

      ::selection {
        background: rgb(217 148 74 / 0.35);
        color: var(--text);
      }

      /* This page is about scrolling, so the thing you are moving should be
         visible and take the page's colours rather than the browser's. Styling
         these pseudo-elements also opts Chromium out of overlay scrollbars, so
         the bar holds its own column instead of floating over the content and
         fading away. Firefox takes the two-value form below. */
      ::-webkit-scrollbar {
        width: 10px;
      }

      ::-webkit-scrollbar-track {
        background: var(--surface);
      }

      ::-webkit-scrollbar-thumb {
        background: #3c4552;
        border-radius: var(--r-sm);
        border: 2px solid var(--surface);
      }

      ::-webkit-scrollbar-thumb:hover {
        background: var(--accent);
      }

      @supports not selector(::-webkit-scrollbar) {
        html {
          scrollbar-width: thin;
          scrollbar-color: #3c4552 var(--surface);
        }
      }

      /* macOS hides the real scrollbar until you scroll, and never shows it in a
         screen capture, so the page carries its own position marker. It rides a
         scroll timeline rather than a scroll listener: no JavaScript, and none of
         the per-frame work this library exists to avoid. Browsers without scroll
         timelines get nothing, which is why the rail is hidden by default. */
      .rail {
        display: none;
        position: fixed;
        top: 0;
        right: 0;
        z-index: 5;
        width: 5px;
        height: 100vh;
        height: 100dvh;
        background: var(--border);
      }

      .rail span {
        display: block;
        width: 100%;
        height: 56px;
        border-radius: var(--r-sm);
        background: var(--accent);
      }

      @supports (animation-timeline: scroll()) {
        .rail {
          display: block;
        }

        .rail span {
          animation: rail linear;
          animation-timeline: scroll(root block);
        }
      }

      @keyframes rail {
        from {
          transform: translateY(0);
        }
        to {
          transform: translateY(calc(100dvh - 56px));
        }
      }

      a {
        color: var(--text);
        text-decoration-thickness: 1px;
        text-underline-offset: 0.18em;
        text-decoration-color: var(--muted);
      }

      a:hover {
        text-decoration-color: var(--accent);
      }

      :focus-visible {
        outline: 2px solid var(--accent);
        outline-offset: 3px;
        border-radius: var(--r-sm);
      }

      main {
        max-width: 880px;
        margin: 0 auto;
        padding: 0 24px;
      }

      h1,
      h2,
      h3 {
        text-wrap: balance;
      }

      p {
        text-wrap: pretty;
      }

      .top {
        display: flex;
        align-items: center;
        justify-content: space-between;
        height: var(--nav-height);
        font-size: 0.95rem;
      }

      .top .name {
        font-weight: 500;
        text-decoration: none;
      }

      .top .links {
        display: flex;
        gap: 20px;
      }

      .hero {
        position: relative;
        /* Fill the first screen minus the bar above it, using the small viewport
           so the caret does not jump when a phone's address bar collapses. */
        min-height: calc(100vh - var(--nav-height));
        min-height: calc(100svh - var(--nav-height));
        display: flex;
        flex-direction: column;
        justify-content: center;
        gap: 14px;
        padding-bottom: 12vh;
      }

      .hero h1 {
        font-size: clamp(2.2rem, 5.2vw, 3.5rem);
        font-weight: 600;
        /* Display type sets its own leading; the body's 1.6 leaves headlines
           floating apart. 1.08 still clears the italic's descenders. */
        line-height: 1.08;
        margin: 0;
        letter-spacing: -0.02em;
        max-width: 18ch;
      }

      /* Emphasis inside a headline belongs to the same typeface. Italic reads as
         intent; a gradient fill reads as decoration looking for a job. */
      .hero h1 em {
        font-style: italic;
        font-weight: 500;
        /* Descender clearance, so the italic never clips against tight leading. */
        line-height: 1.1;
        padding-bottom: 0.06em;
      }

      .hero p {
        color: var(--muted);
        font-size: 1.05rem;
        max-width: 44ch;
        margin: 0;
      }

      /* The tease: an invitation to scroll, anchored to the foot of the first
         screen. It nudges down and then rests, rather than metronoming, so it
         reads as a gesture rather than a loading indicator. */
      .tease {
        position: absolute;
        bottom: 4vh;
        left: 50%;
        display: grid;
        place-items: center;
        width: 44px;
        height: 44px;
        padding: 0;
        background: none;
        border: 0;
        border-radius: 999px;
        color: var(--accent);
        cursor: pointer;
        transform: translateX(-50%);
        transition: transform 160ms var(--ease-out);
      }

      /* Press feedback lives on the button, not the bobbing span: the keyframe
         animation owns that span's transform and would swallow it. */
      .tease:active {
        transform: translateX(-50%) scale(0.94);
      }

      .tease:focus-visible {
        outline: 2px solid var(--accent);
        outline-offset: 2px;
      }

      @media (hover: hover) and (pointer: fine) {
        .tease:hover .chevron {
          opacity: 1;
        }
      }

      .tease:focus-visible .chevron {
        opacity: 1;
      }

      .bob {
        display: block;
        animation: bob 1.5s ease-in-out infinite;
      }

      .chevron {
        display: block;
        width: 13px;
        height: 13px;
        margin-top: -5px;
        border-right: 2px solid currentColor;
        border-bottom: 2px solid currentColor;
        transform: rotate(45deg);
        opacity: 0.75;
        transition: opacity 200ms ease;
      }

      @keyframes bob {
        0% {
          transform: translateY(0);
        }
        45% {
          transform: translateY(8px);
        }
        70%,
        100% {
          transform: translateY(0);
        }
      }

      @media (prefers-reduced-motion: reduce) {
        .bob {
          animation: none;
        }
        .tease {
          transition: none;
        }
      }

      /* Each example gets a screen's worth of room, so its reveal is seen alone. */
      section {
        padding: 22vh 0;
        border-top: 1px solid var(--border);
      }

      section h2 {
        margin: 0 0 8px;
        font-size: 1.75rem;
        font-weight: 600;
        line-height: 1.2;
        letter-spacing: -0.02em;
      }

      section > p {
        color: var(--muted);
        margin: 0 0 40px;
        max-width: 62ch;
      }

      .card {
        background: var(--surface);
        border: 1px solid var(--border);
        border-radius: var(--r);
        padding: 28px;
      }

      .card h3 {
        margin: 0 0 6px;
        font-size: 1.05rem;
        font-weight: 600;
      }

      .card p {
        margin: 0;
        color: var(--muted);
        font-size: 0.9rem;
      }

      .row {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
        gap: 16px;
      }

      /* A lone card should look like a card, not a banner. */
      .row.single {
        grid-template-columns: minmax(0, 420px);
      }

      /* The left and right examples travel 40px sideways while hidden. On a phone
         the cards are full width, so that travel would reach past the viewport and
         give the page a horizontal scrollbar. Clip contains it without creating a
         scroll container, so the slide still reads as arriving from the edge. */
      #directions .row {
        overflow-x: clip;
      }

      .grid {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 16px;
      }

      .grid .card {
        aspect-ratio: 4 / 3;
        display: flex;
        flex-direction: column;
        justify-content: space-between;
        font-size: 0.85rem;
        color: var(--muted);
      }

      /* The numerals are the order of arrival: they are what the cascade shows. */
      .stagger-cell b {
        font-size: 1.6rem;
        font-weight: 600;
        font-variant-numeric: tabular-nums;
        color: var(--accent);
      }

      /* A bar per cell, so the cascade has a shape to travel along. */
      .stagger-cell i {
        display: block;
        height: 5px;
        border-radius: var(--r-sm);
        background: var(--accent);
        opacity: 0.5;
      }

      code {
        font-family: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, monospace;
        font-size: 0.85em;
        background: var(--surface);
        border: 1px solid var(--border);
        border-radius: var(--r-sm);
        padding: 2px 6px;
      }

      footer {
        display: flex;
        justify-content: space-between;
        gap: 24px;
        flex-wrap: wrap;
        border-top: 1px solid var(--border);
        padding: 40px 0 64px;
        color: var(--muted);
        font-size: 0.85rem;
      }

      footer p {
        margin: 0;
      }

      footer > div {
        display: grid;
        gap: 6px;
      }

      @media (max-width: 640px) {
        section {
          padding: 18vh 0;
        }

        .card {
          padding: 20px;
        }

        .grid {
          gap: 10px;
        }

        .grid .card {
          padding: 14px;
        }

        .stagger-cell b {
          font-size: 1.25rem;
        }
      }
    </style>
  </head>
  <body>
    <div class="rail" aria-hidden="true"><span></span></div>

    <main>
      <nav class="top" aria-label="Site">
        <a class="name" href="./">appear-on-scroll</a>
        <span class="links">
          <a href="https://www.npmjs.com/package/appear-on-scroll">npm</a>
          <a href="https://github.com/davemaynard/appear-on-scroll">GitHub</a>
        </span>
      </nav>

      <header class="hero">
        <h1>Elements that <em>arrive</em> with the scroll.</h1>
        <p>Reveal any element on scroll, with a slide that knows which way you scrolled. No dependencies.</p>

        <button class="tease" type="button" aria-label="Scroll to the first example">
          <span class="bob"><span class="chevron"></span></span>
        </button>
      </header>

      <section id="slide">
        <h2>Direction-aware slide</h2>
        <p>
          The default. Cards rise into place as you scroll down, and settle from above when you scroll back up to them.
          The IntersectionObserver entry says which edge was crossed, so there is no scroll listener.
        </p>
        <div class="row">
          <div class="card" data-slide id="dir-el">
            <h3>Watch me twice</h3>
            <p>Pass me going down, then come back up. I arrive from whichever side you approached.</p>
          </div>
          <div class="card" data-slide>
            <h3>Same batch</h3>
            <p>Everything in a section follows the same scroll direction.</p>
          </div>
        </div>
      </section>

      <section id="directions">
        <h2>Pinned directions</h2>
        <p>Set <code>direction</code> and the slide ignores which way you scrolled.</p>
        <div class="row">
          <div class="card" data-dir-up>
            <h3>up</h3>
            <p>Rises from below.</p>
          </div>
          <div class="card" data-dir-down>
            <h3>down</h3>
            <p>Drops from above.</p>
          </div>
          <div class="card" data-dir-left>
            <h3>left</h3>
            <p>Slides in from the right.</p>
          </div>
          <div class="card" data-dir-right>
            <h3>right</h3>
            <p>Slides in from the left.</p>
          </div>
        </div>
      </section>

      <section id="fade">
        <h2>Fade</h2>
        <p>
          <code>animation: 'fade'</code>. No movement, only opacity. The v1 spelling, <code>slide: false</code>, still
          works.
        </p>
        <div class="row single">
          <div class="card" data-fade id="fade-el">
            <h3>Fade</h3>
            <p>The quiet option.</p>
          </div>
        </div>
      </section>

      <section id="zoom">
        <h2>Zoom</h2>
        <p><code>animation: 'zoom'</code> with <code>scale: 0.9</code>. Grows to full size while fading in.</p>
        <div class="row single">
          <div class="card" data-zoom>
            <h3>Zoom</h3>
            <p>Starts at 90% scale.</p>
          </div>
        </div>
      </section>

      <section id="blur">
        <h2>Blur</h2>
        <p><code>animation: 'blur'</code>. Sharpens into focus while fading in.</p>
        <div class="row single">
          <div class="card" data-blur>
            <h3>Blur</h3>
            <p>From soft focus to sharp.</p>
          </div>
        </div>
      </section>

      <section id="stagger">
        <h2>Stagger</h2>
        <p>
          <code>stagger: 90</code>. Elements arriving together each wait 90ms longer than the one before, so a grid
          cascades instead of popping in at once. The wave is measured in time rather than in observer batches, so the
          cascade looks the same however fast you scrolled into it.
        </p>
        <div class="grid">
          <div class="card stagger-cell"><b>01</b><i style="width: 64%"></i></div>
          <div class="card stagger-cell"><b>02</b><i style="width: 42%"></i></div>
          <div class="card stagger-cell"><b>03</b><i style="width: 88%"></i></div>
          <div class="card stagger-cell"><b>04</b><i style="width: 30%"></i></div>
          <div class="card stagger-cell"><b>05</b><i style="width: 74%"></i></div>
          <div class="card stagger-cell"><b>06</b><i style="width: 52%"></i></div>
          <div class="card stagger-cell"><b>07</b><i style="width: 96%"></i></div>
          <div class="card stagger-cell"><b>08</b><i style="width: 38%"></i></div>
          <div class="card stagger-cell"><b>09</b><i style="width: 68%"></i></div>
        </div>
      </section>

      <section id="once">
        <h2>Replay, or once</h2>
        <p>
          Elements hide again when they leave the viewport and replay on the way back. With <code>once: true</code> the
          first appearance sticks.
        </p>
        <div class="row">
          <div class="card" data-again id="again-el">
            <h3>once: false</h3>
            <p>Scroll away and back. I replay every time.</p>
          </div>
          <div class="card" data-once id="once-el">
            <h3>once: true</h3>
            <p>I appear once and never hide again.</p>
          </div>
        </div>
      </section>

      <footer>
        <div>
          <p>Zero dependencies. Under 3 KB gzipped. Honours <code>prefers-reduced-motion</code>.</p>
          <p>npm still carries the 1.x line, which has a different API. Version 2 builds from source.</p>
        </div>
        <p>Built by <a href="https://davemaynard.dev">Dave Maynard</a></p>
      </footer>
    </main>

    <script type="module">
      import {AppearOnScroll} from '../dist/index.js';

      const instances = [
        new AppearOnScroll('[data-slide]', {duration: 900}),
        new AppearOnScroll('[data-dir-up]', {direction: 'up'}),
        new AppearOnScroll('[data-dir-down]', {direction: 'down'}),
        new AppearOnScroll('[data-dir-left]', {direction: 'left', distance: '40px'}),
        new AppearOnScroll('[data-dir-right]', {direction: 'right', distance: '40px'}),
        new AppearOnScroll('[data-fade]', {animation: 'fade'}),
        new AppearOnScroll('[data-zoom]', {animation: 'zoom', scale: 0.9}),
        new AppearOnScroll('[data-blur]', {animation: 'blur'}),
        new AppearOnScroll('.stagger-cell', {stagger: 90, duration: 500}),
        new AppearOnScroll('[data-again]', {once: false}),
        new AppearOnScroll('[data-once]', {once: true}),
      ];

      // Test hook: lets the Playwright suite call destroy() on everything.
      window.__aosInstances = instances;

      document.querySelector('.tease').addEventListener('click', () => {
        document.getElementById('slide').scrollIntoView({behavior: 'smooth', block: 'start'});
      });
    </script>
  </body>
</html>