求大神们帮忙看下这段 代码 和算法

</script>
<script type="text/javascript">
    function closeTop(day) {
        document.getElementById("topFloat").style.display = "none";
        document.getElementById("top_hidden").style.display="none";
        SetCookie_top('dd_top_url', '1', day);
    }
    function SetCookie_top(name, value, day)
    {
        var exp = new Date();
        exp.setTime(exp.getTime() + parseInt(day) * 24 * 60 * 60 * 1000);
        document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString() + ";path=/;domain=
    }
    function getCookie_top(name)//取cookies函数        
    {
        var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
        if (arr != null) return unescape(arr[2]); return null;

    }
    function showSiteTop(i) {
        if (i < 70) {
            var hh = i - 70;
            document.getElementById("topFloat").style.top = hh + "px";
            i = i + 1;
            setTimeout("showSiteTop(" + i + ")", 30);
        }
    }
    var mob_status = 1;
    //alert(vip_level);
    if(mob_status != 1){
        if (getCookie_top('dd_top_url') != 1) {
            //showSiteTop(0);
            document.getElementById("topFloat").style.display = "";
            document.getElementById("top_hidden").style.display="";
        }
    }
    function showSiteTop2(i) {
        if (i <= 22) {
            i++;
            setTimeout("showSiteTop2(" + i + ")", 50);
        }