// javascript document
function gotopex() {
    var obj = document.getelementbyid("zhiding");
    function getscrolltop() {
        return $(window).scrolltop();
    }
    function setscrolltop(value) {
        $(window).scrolltop(value);
    }
    window.onscroll = function () { getscrolltop() > 700 ? obj.style.display = "" : obj.style.display = "none"; }
    obj.onclick = function () {
        var gotop = setinterval(scrollmove, 15);
        function scrollmove() {
            setscrolltop(getscrolltop() / 1.1);
            if (getscrolltop() < 1) clearinterval(gotop);
        }
    }
}