JavaScript TypeError: Cannot read property 'style' of null for scroll

Question

I need to fix this but I dont know how to do it. I think it is easy but I am not good at js. But this codes work well.

 var prevScrollpos = window.pageYOffset; window.onscroll = function () { var currentScrollPos = window.pageYOffset; if (prevScrollpos > currentScrollPos) { document.getElementById("w-sticky-header").style.top = "0"; } else { document.getElementById("w-sticky-header").style.top = "-50px"; } prevScrollpos = currentScrollPos; }

This is my sticky header js code. But it results in an alert as seen in the picture:

Answer 1

Well technically it means code could not find element with given id. Please check your html that it does have this element with id.