old_contents: $(document).ready(function() {
      var $header = $("#mainSearch"),
          $clone = $header.before($header.clone().addClass("clone"));
  
      $(window).on("scroll", function() {
          var fromTop = $("html,body").scrollTop();
          $clone.toggleClass("down", (fromTop > 400));
      });
  });
new_contents: /*$(document).ready(function() {
      var $header = $("#mainSearch"),
          $clone = $header.before($header.clone().addClass("clone"));
  
      $(window).on("scroll", function() {
          var fromTop = $("html,body").scrollTop();
          $(window).toggleClass("down", (fromTop > 400));
      });
  });*/
  
  
  $(document).ready(function() {
  
  	var $search = $("mainSearch");
  
  	$(window).on("scroll", function() {
  
  		var fromTop = $("html, body").scrollTop();
  		var pos = $search.position();
  		$search.toggleClass("down", (fromTop > pos.top));
  
  	});
  
  });
subject: test searchbar