用JS写的一个cookies判断后事件触发过程

/*
*@desc Cookie工具,提供对Cookie的增、删、查
*@param expireDays 设置Cookie的有效时间单位为:天
* 如未指定则默认为30天
*/
var CookieUitl = function(expireDays)
{
    //根据参数设置Cookie有效时间，如未指定默认为30天
    if(expireDays)
        this.expireDays = expireDays;
    else
        this.expireDays = 30;
    /*
     *@desc 设置Cookie
     *@param key Cookie的名称
     *@param value Cookie的值
     */
    this.setCookie = function(key,value)
    {
        var exp = new Date();
        var times = this.expireDays * 24 * 60 * 60 * 1000;
        exp.setTime(exp.getTime() + times );
        document.cookie = key + "=" + escape(value) +";expires=" + exp.toGMTString();
    }
    /*
     *@desc 获得指定Cookie的值
     *@param key Cookie名称
     */
    this.getCookie = function(key)
    {
        var arr = document.cookie.match(new RegExp("(^| )"+key+"=([^;]*)(;|$)"));
        if(arr != null)
            return unescape(arr[2]);
        return null;
    }
    /*
     *@desc 删除指定Cookie
     *@param key 要删除的Cookie名称
     */
    this.delCookie = function(key)
    {
        var exp = new Date();
        exp.setTime(exp.getTime() - 1);
        var cval=this.getCookie(key);
        if(cval!=null) document.cookie= key + "="+cval+";expires="+exp.toGMTString();
    }
}

//当页面加载时初始化工具栏状态
function initToolbar()
{
    var c = new  CookieUitl().getCookie("ToolbarStatus");
    if(c == "expand")
        toolbar.hide();
    else
        toolbar.show();
    if((c != "colspan") && (c != "expand"))
        saveToolBar("colspan");
}

//存储工具栏状态
function saveToolBar(value)
{
    new  CookieUitl().setCookie("ToolbarStatus",value);
}