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","");
}
}