javascript onscroll sticky navbar

  // When the user scrolls the page, execute myFunction 
window.onscroll = 
  function() {myFunction()};

// Get the header
var header = document.getElementById("myHeader");

  
// 
  Get the offset position of the navbar
var sticky = 
  header.offsetTop;

// Add the sticky class to the header when you reach 
  its scroll position. Remove "sticky" when you leave the scroll position
function myFunction() {
  if (window.pageYOffset 
  > sticky) {
    header.classList.add("sticky");
  } 
  else {
    header.classList.remove("sticky");
  }

  } 

  /* Style the header */
.header {
  padding: 
  10px 16px;
  background: #555;
  color: #f1f1f1;
}

/* Page content */
.content {
  padding: 16px;
}

/* 
  The sticky class is added to the header with JS when it reaches its scroll 
  position */
.sticky {
  
  position: fixed;
  top: 0;
  width: 100%
}

/* Add 
  some top padding to the page content to prevent sudden quick movement (as the 
  header gets a new position at the top of the page (position:fixed and 
  top:0) */
.sticky + .content {
  
  padding-top: 102px;
}