$(function () { 
	var $index=$('.topic-index');
	$index.empty();
	$('.topic-title').each(function(){
		var $topic=$('<li>').addClass('index-topic-title').appendTo($index);
		$('<a href="#'+$(this).attr('id')+'">').text($(this).attr('id').toLowerCase()).appendTo($topic);

	});
  
$('.wrapper').on('scroll', function() {
        	$('.topic-title').each(function() {
        		if($(this).isOnTopScreen()){
        			var elemId = $(this).attr('id');
        			$("a.topic-active").removeClass('topic-active');
        			$("a[href='#" + elemId + "']").addClass('topic-active');
        		}

        	});
});
});

  
  
	$.fn.isOnTopScreen = function() {
		var elementTop = $(this).offset().top;
		var elementBottom = elementTop + $(this).outerHeight();

		var viewportTop = $(window).scrollTop();
		var viewportBottom = viewportTop + $(window).height();

		return elementTop < viewportBottom;
	};
	$.fn.isOnBottomScreen = function() {
		var elementTop = $(this).offset().top;
		var elementBottom = elementTop + $(this).outerHeight();

		var viewportTop = $(window).scrollTop();
		var viewportBottom = viewportTop + $(window).height();

		return elementBottom > viewportTop;
	};






/*******************************************************************/
/* ftrtch dino */
/* [type: JS] [file:mobile-nav] [36.264] DESIGN*/
/*******************************************************************/
/* 0.2 D>D */
/* db 144 */