var record = 20; //每页显示多少条记录
    var count = document.getElementById("mytable").rows.length ;  // 24; //总记录数
    var pageTotal = ((count + record - 1) / record) | 0; //总页数 
    var pagenum = 1; //将要显示的页码 

    Cookie = {
        Set: function() {
            var name = arguments[0], value = escape(arguments[1]), days = 365, path = "/";
            if (arguments.length > 2) days = arguments[2];
            if (arguments.length > 3) path = arguments[3];
            with (new Date()) {
                setDate(getDate() + days);
                days = toUTCString();
            }
            document.cookie = "{0}={1};expires={2};path={3}".format(name, value, days, path);
        },
        Get: function() {
            var returnValue = document.cookie.match(new RegExp("[\b\^;]?" + arguments[0] + "=([^;]*)(?=;|\b|$)", "i"));
            return returnValue ? unescape(returnValue[1]) : returnValue;
        }
    }
    String.prototype.format = function() {
        var tmpStr = this;
        var iLen = arguments.length;
        for (var i = 0; i < iLen; i++) {
            tmpStr = tmpStr.replace(new RegExp("\\{" + i + "\\}", "g"), arguments[i]);
        }
        return tmpStr;
    }
    function setPagenum() {//整理Cookie 
        pagenum = Cookie.Get("pagenum");
        if (pagenum == "" || pagenum < 1) {
            pagenum = 1;
        }
    }

    setPagenum();

    //重新整理当前页码，如果页面小于1，则赋值为1，如果大于总页数，则等于总页数 
    coordinatePagenum(pagenum);

    //根据当前要显示的页码取得当前面里第一条记录的号码 
    var pageBegin = (record * (pagenum - 1) + 1) | 0;

    //根据当前要显示的页码取得当前面里最后一条记录的号码 
    var pageEnd = record * pagenum;

    function showhiddenRecord(pagenum) {
        number.innerHTML = pagenum;
        
        if (pagenum <= 1) {
            theFirstPage.innerHTML = "<img src=\"/images/bu_grid_pre2.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\">";
            thePrePage.innerHTML = "<img src=\"/images/bu_grid_pre.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\">";
        } else {
            theFirstPage.innerHTML = "<a href=\"javascript:firstPage()\"><img src=\"/images/bu_grid_pre2.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\"></a>";
            thePrePage.innerHTML = "<a href=\"javascript:prePage()\"><img src=\"/images/bu_grid_pre.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\"></a>";
        }
        if (pagenum >= pageTotal) {
            theNextPage.innerHTML = "<img src=\"/images/bu_grid_next.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\">";
            theLastPage.innerHTML = "<img src=\"/images/bu_grid_next2.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\">";
        } else {
            theNextPage.innerHTML = "<a href=\"javascript:nextPage()\"><img src=\"/images/bu_grid_next.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\"></a>";
            theLastPage.innerHTML = "<a href=\"javascript:lastPage()\"><img src=\"/images/bu_grid_next2.gif\" width=\"25\" height=\"19\" border=\"0\" align=\"absmiddle\"></a>";
        }
        document.getElementById('goto').value = pagenum;
        //根据当前要显示的页码取得当前面里第一条记录的号码 
        pageBegin = (record * (pagenum - 1) ) | 0;

        //根据当前要显示的页码取得当前面里最后一条记录的号码 
        pageEnd = record * pagenum;
        for (var i = 0; i <= count-1; i++) {
            if (i >= pageBegin && i < pageEnd) {
                mytable.rows[i].style.display = "";
            } else {
                mytable.rows[i].style.display = "none";
            }
        }
        Cookie.Set("pagenum", pagenum);
    }

    function firstPage() {
        pagenum = 1;
        showhiddenRecord(pagenum);
    }

    function lastPage() {
        showhiddenRecord(pageTotal);
    }

    //重新整理当前页码，如果页面小于1，则赋值为1，如果大于总页数，则等于总页数 
    function coordinatePagenum(num) {
        if (num < 1) {
            num = "1";
        } else if (num > pageTotal) {
            num = pageTotal;
        }
    }

    function prePage() {
        pagenum--;
        coordinatePagenum(pagenum);
        showhiddenRecord(pagenum);
    }

    function nextPage() {
        pagenum++;
        coordinatePagenum(pagenum);
        showhiddenRecord(pagenum);
    }

    function gotoPage(num) {
        coordinatePagenum(pagenum);
        showhiddenRecord(num);
    }

    // 
    showhiddenRecord(pagenum);
    //debugger;
    var ddl = document.getElementById("goto");
    ddl.options.length = 0;
    for (var i = 0; i < pageTotal; i++) {
        ddl.options[i] = new Option(i + 1, i + 1);
    }
   theTotalNum.innerHTML=count;
    theTotalPage.innerHTML=pageTotal;