Smooth transition between static and fixed div header

Question

<script>
window.onscroll = function() {scrollFunction()};

function scrollFunction() {
if (document.body.scrollTop > 320 || document.documentElement.scrollTop > 
320) {
document.getElementById("header").style.position = "fixed";
} else {
document.getElementById("header").style.position = "static";
}
}
</script>

I have this JavaScript that makes the header div scroll down and stay in a fixed position at 320px, the only problem is that the header pops up roughly. How can I make the transition between static position to fixed smoothy?

Answer 1

Try this for both of your conditions:

document.getElementById("header").style.transition = "all 2s";

A life example is given in W3school here .