var StickyElement = function(node){
   var doc = $(document),  
       fixed = false,
       anchor = node.find('.sticky-anchor'),
       content = node.find('.sticky-content');
    
   var onScroll = function(e){
     var docTop = doc.scrollTop(),
         anchorTop = anchor.offset().top;
      
     console.log('scroll', docTop, anchorTop);
     if(docTop > anchorTop){
       if(!fixed){
         anchor.height(content.outerHeight());
         content.addClass('fixed');         
         fixed = true;
       }
     }  else   {
       if(fixed){
         anchor.height(0);
         content.removeClass('fixed');  
         fixed = false;
       }
     }
   };
    
   $(window).on('scroll', onScroll);
};

var demo = new StickyElement($('#sticky'));     

.sticky-content.fixed{
   position: fixed;
   top: 0;
   left: 0;
   right: 0;
}

.sticky-content.fixed{
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
}