sticky header on scroll
*****************HTML****************
<div class="sticky"></div>
*****************CSS****************
.fixed {
position: fixed;
top:0; left:0;
width: 100%; }
******************jQuery***************
$(window).scroll(function(){
var sticky = $('.sticky'),
scroll = $(window).scrollTop();
if (scroll >= 100) sticky.addClass('fixed');
else sticky.removeClass('fixed');
});