js页面滚动插件

// 平滑滚动函数
function smoothScroll(target, duration) {
  var targetElement = document.querySelector(target);
  var targetPosition = targetElement.getBoundingClientRect().top;
  var startPosition = window.pageYOffset;
  var distance = targetPosition;
  var startTime = null;

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

  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);
}

// 使用示例
document.querySelector('button').addEventListener('click', function() {
  smoothScroll('#targetElement', 1000);
});