// javascript document
$(function(){
  $(window).on("scroll",function(){
    scrollhandler();
  }).scroll();
			
  function scrollhandler(){
	var scrolltop=$(window).scrolltop(); 
	var windowheight=$(window).height();

	$(".section").each(function(i,dom){	  
	  if($(dom).offset().top-scrolltop<=windowheight+350-200){
		$(dom).addclass("active");
	  }; 
	});	
  }					
})