JS实现刷新页面后回到记录时滚动条的位置

window.onbeforeunload = function () {
    var scrollPos;
    if (typeof window.pageYOffset != 'undefined') {
        scrollPos = window.pageYOffset;
    }
    else if (typeof document.compatMode != 'undefined' && document.compatMode != 'BackCompat') {
        scrollPos = document.documentElement.scrollTop;
    }
    else if (typeof document.body != 'undefined') {
        scrollPos = document.body.scrollTop;
    }
    document.cookie = "scrollTop=" + scrollPos; //存储滚动条位置到cookies中
}

$(window).load(function () {
    if (document.cookie.match(/scrollTop=([^;]+)(;|$)/) != null) {
        var arr = document.cookie.match(/scrollTop=([^;]+)(;|$)/); //cookies中不为空，则读取滚动条位置
        document.documentElement.scrollTop = parseInt(arr[1]);
        document.body.scrollTop = parseInt(arr[1]);
    }
});

//滚动条会到顶部
function scrollTop() {
    document.documentElement.scrollTop = 0;
    document.body.scrollTop = 0;
}