sticky-scroll

$(function(){ // document ready
 
  if (!!$('.sticky').offset()) { // make sure ".sticky" element exists
 
    var stickyTop = $('.sticky').offset().top; // returns number 
 
    $(window).scroll(function(){ // scroll event
 
      var windowTop = $(window).scrollTop(); // returns number 
 
      if (stickyTop < windowTop){
        $('.sticky').css({ position: 'fixed', top: 0 });
      }
      else {
        $('.sticky').css('position','static');
      }
 
    });
 
  }
 
});