$(window).scroll(function(){
var $sections = $('section');
$sections.each(function(i,el){
var top = $(el).offset().top-100;
var bottom = top +$(el).height();
var scroll = $(window).scrollTop();
var id = $(el).attr('id');
if( scroll > top && scroll < bottom){
$('a.active').removeClass('active');
$('a[href="#'+id+'"]').addClass('active');
}
})
});$('.characteristics .color-6').click(function(event) {
var thisColorNumber = $(this).attr('data-num6');
alert(thisColorNumber);
});<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>Гостиницы</title>
<link href="css/normalize.css" rel="stylesheet" />
<link rel="stylesheet" href="./css/index-css.css" type="text/css" />
<link href="https://fonts.googleapis.com/css?family=PT+Sans:400,700&subset=cyrillic" rel="stylesheet" />
</head>
<body>