Function updateFunction

js/custom.js:33–54

()

    });

    var updateFunction = function () {
        var id = null;
        var elements = document.getElementsByClassName("header");
        Array.prototype.forEach.call(elements, function (el) {
            if (window.pageYOffset >= el.offsetTop) {
                id = el;
            }
        });

        Array.prototype.forEach.call(document.getElementsByClassName("pagetoc")[0].children, function (el) {
            el.classList.remove("active");
        });

        Array.prototype.forEach.call(document.getElementsByClassName("pagetoc")[0].children, function (el) {
            if (id == null) {
                return;
            }
            if (id.href.localeCompare(el.href) == 0) {
                el.classList.add("active");
            }
        });
    };

    var pagetoc = document.getElementsByClassName("pagetoc")[0];
    var elements = document.getElementsByClassName("header");