$(document).ready(function () {
    var pub_head_title = $('.index_pub_head_title h2');
    var countPubHeadTitle = pub_head_title.length;
    var firstPubHeadTitle = pub_head_title.eq(0);
    
    var fixed_nav = $("#index_fixed_nav_container");
    var nav_ul = fixed_nav.children('ul');
    var nav_li_html = '';
    pub_head_title.each(function () {
        nav_li_html = nav_li_html + '<li><div class="t_layout"><span>' + $(this).text() + '</span></div></li>';
    });
    nav_ul.append(nav_li_html);
    var nav_li = nav_ul.children('li');
    
    nav_li.eq(0).click(function () {
        $('html,body').animate({'scrollTop' : 0});
    });
    nav_li.filter(':gt(0)').click(function () {
        var this_index = $(this).index();
        var toTop = pub_head_title.eq(this_index - 1).offset().top;
        var nextHeadTitle = pub_head_title.eq(this_index);
        if (nextHeadTitle.length > 0) {
            var nextPartitionTop = nextHeadTitle.offset().top - $(window).height() / 1.5;
            if (toTop >= nextPartitionTop) {
                toTop = nextPartitionTop;
            }
        }
        toTop = toTop - 20;
        $('html,body').animate({'scrollTop' : toTop});
    });
    
    function OnScroll() {
        var windowScrollTop = $(window).scrollTop();
        if (windowScrollTop >= firstPubHeadTitle.offset().top - $(window).height() / 2.7) {
            fixed_nav.addClass('on');
        }
        else {
            fixed_nav.removeClass('on');
            return;
        }
        
        var i;
        for (i = countPubHeadTitle - 1; i >= 0; i--) {
            var theTitle = pub_head_title.eq(i);
            if (windowScrollTop >= theTitle.offset().top - $(window).height() / 1.5) {
                var theLi = nav_li.eq(i + 1);
                theLi.siblings('li').removeClass('on');
                theLi.addClass('on');
                break;
            }
        }
    }
    OnScroll();
    $(window).scroll(function () {
        OnScroll();
    });
});