Answers for "navbar sticky W3"

stick menu bar in css

.navigation {
   /* fixed keyword is fine too */
   position: sticky;
   top: 0;
   z-index: 100;
   /* z-index works pretty much like a layer:
   the higher the z-index value, the greater
   it will allow the navigation tag to stay on top
   of other tags */
}

sticky operations in javascript

var siteHeader = document.getElementById('siteHeader'),
    siteNav = document.getElementById('siteNav');

    window.onscroll = function() {
        if ( siteNav.offsetTop < document.documentElement.scrollTop + 26 || siteNav.offsetTop < document.body.scrollTop + 26) {
            siteHeader.setAttribute("class","sticky");
        }
        else {
            siteHeader.setAttribute("class","");
        }
    }