js平滑滚动到顶部

function scrollToTop() {
  window.scrollTo({
    top: 0,
    behavior: 'smooth'
  });
}

document.getElementById('back-to-top-button').addEventListener('click', function() {
  this.scrollIntoView({ behavior: 'smooth' });
});

function smoothScrollToTop(duration) {
  const start = window.pageYOffset;
  const startTime = 'now' in window.performance ? performance.now() : new Date().getTime();

  function scroll() {
    const time = 'now' in window.performance ? performance.now() : new Date().getTime();
    const timeElapsed = time - startTime;
    const progress = Math.min(timeElapsed / duration, 1);
    window.scrollTo(0, start * (1 - progress));

    if (timeElapsed < duration) {
      requestAnimationFrame(scroll);
    }
  }

  requestAnimationFrame(scroll);
}

// 使用方法
document.getElementById('back-to-top-button').addEventListener('click', function() {
  smoothScrollToTop(600); // 600毫秒内滚动到顶部
});