Autoscroll on Page Load for Colin

gistfile1.js

document.addEventListener('DOMContentLoaded', function () {

  if (window.__autoScroll) {
    cancelAnimationFrame(window.__autoScroll.raf);
    window.__autoScroll.cleanup();
  }

  const pxPerSecond = 40; // ← adjust speed here
  let last = null;

  const scrollKeys = new Set([
    'ArrowUp', 'ArrowDown', 'PageUp', 'PageDown', 'Home', 'End', ' '
  ]);

  function stop(reason) {
    if (!window.__autoScroll) return;
    cancelAnimationFrame(window.__autoScroll.raf);
    window.__autoScroll.cleanup();
    window.__autoScroll = null;
    console.log(`Auto-scroll stopped (${reason}).`);
  }

  function onUserInput(e) {
    if (e.type === 'keydown' && !scrollKeys.has(e.key)) return;
    stop('user input detected');
  }

  function step(now) {
    if (last === null) last = now;
    const dt = (now - last) / 1000;
    last = now;

    window.scrollBy(0, pxPerSecond * dt);

    const atBottom =
      window.innerHeight + window.scrollY >=
      document.documentElement.scrollHeight - 1;

    if (!atBottom) {
      window.__autoScroll.raf = requestAnimationFrame(step);
    } else {
      stop('reached bottom');
    }
  }

  window.addEventListener('wheel', onUserInput, { passive: true });
  window.addEventListener('touchstart', onUserInput, { passive: true });
  window.addEventListener('keydown', onUserInput);

  window.__autoScroll = {
    raf: requestAnimationFrame(step),
    cleanup() {
      window.removeEventListener('wheel', onUserInput);
      window.removeEventListener('touchstart', onUserInput);
      window.removeEventListener('keydown', onUserInput);
    }
  };

  window.__stopScroll = () => stop('manual stop');

});