頁面刷新指定到原先滾動條位置

//頁面刷新指定到原先滾動條位置
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; //存儲滾動條位置到cookies中
    }
    window.onload = function() {
        if(document.cookie.match(/scrollTop=([^;]+)(;|$)/) != null) {
            var arr = document.cookie.match(/scrollTop=([^;]+)(;|$)/); //cookies中不爲空，則讀取滾動條位置
            document.documentElement.scrollTop = parseInt(arr[1]);
            document.body.scrollTop = parseInt(arr[1]);
          }
}