movable nav

moving_nav.js

let sidenavElem = document.getElementsByClassName('sidenav')[0];
        M.Sidenav.init(sidenavElem);

        let nav = document.getElementsByTagName('nav')[0];
        let prevY , currentY ;
        prevY = currentY = 0;

        window.addEventListener('scroll',()=>{
            
            currentY = window.scrollY;

            if(currentY > prevY && currentY > 100){
                nav.setAttribute('style','top:-67px');
            }
            else if(currentY < prevY){
                if(nav.hasAttribute('style')){
                    nav.removeAttribute('style');
                }
            }
            
            prevY = currentY;
           
        })