<script>

window.onscroll = function() {myFunction()};

var header = document.getElementById("nav-main-container");

var sticky = header.offsetTop;

function myFunction() {

  if (window.pageYOffset > sticky) {

    header.classList.add("sticky");

  } else {

    header.classList.remove("sticky");

  }

}

</script>

<script>

var parallax = document.querySelectorAll(".parallax");

var speed = -0.25;

window.onscroll = function() {

[].slice.call(parallax).forEach(function(el, i) {

var windowYOffset = window.pageYOffset,

elBackgrounPos = "100% " + (windowYOffset * speed + i * 500) + "px";

el.style.backgroundPosition = elBackgrounPos;

});

};

</script>

I have used above both code in footer but sticky code is not working

can u please give me solution