Вот код, который отвечает за это. Смотрите, разбирайтесь, тут ничего сложного нет.
var deftitle = document.title;
var defurl = document.location.toString().split('#', 2)[0];
var stPoint = 0, anchors = [], anchTop = [];
$(function(){
anchors[0]="ac_1309";anchors[1]="ac_769";anchors[2]="ac_876";anchors[3]="ac_894";anchors[4]="ac_903";anchors[5]="ac_912";anchors[6]="ac_1158";anchors[7]="ac_1153";anchors[8]="ac_2249";anchors[9]="ac_1128";anchors[10]="ac_767";anchors[11]="ac_2047";anchors[12]="ac_1453";
for(var i = 0; i < 13; i++) {
anchTop[i] = $('#'+anchors[i]).offset().top;
}
var lastrel = '';
$('a[href^="#/"]').bind("click", function(e){popupScroll($(this).attr('href'),true);e.preventDefault();});
if (window.location.hash && window.location.hash.substr(0, 2) == "#/") popupScroll(window.location.hash,false);
$(document).on('keyup', function(e){
if (e.which == 27) $.each($('.popupContent'), function(i, val) {popupClose(val.id.substr(2));});
});
$(window).scroll(function(){
stPoint = $(window).scrollTop();
var rel = '';
for (i = 0; i < 13; i++) {
if ((anchTop[i] - 1) <= stPoint && !$('#'+anchors[i]).parent().parent().hasClass('phidden')) {
rel = anchors[i];
if (anchTop[i+1] != undefined && (anchTop[i+1] - 1) > stPoint || $('#'+anchors[i]).parent().parent().hasClass('popupContent')) break;
}
}
if (lastrel != rel) {
if (lastrel) {
if (rel == 'ac_1309' || rel == '') {
if (deftitle != document.title) document.title = deftitle;
if (history && history.replaceState) history.replaceState(null, null, defurl);
} else {
document.title = $('#'+rel).attr('title')+' '+deftitle;
if (history && history.replaceState) history.replaceState(null, null, '#'+$('#'+rel+' span').attr('id'));
}
}
lastrel = rel;
$('.anchors').removeClass('msel');
if (rel) $('.'+rel).addClass('msel');
}
});
$(window).trigger('scroll');
});
