如何在整个网站页面中停止向下滚动页眉

header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
}

window.addEventListener('scroll', function() {
  var header = document.querySelector('header');
  var scrollPosition = window.scrollY || window.pageYOffset;
  
  if (scrollPosition > 100) {
    header.style.position = 'fixed';
    header.style.top = '0';
    header.style.left = '0';
    header.style.width = '100%';
  } else {
    header.style.position = 'static';
  }
});

$(document).ready(function() {
  $('header').sticky();
});