请帮忙改一段JS代码，加入Cookie操作控制层的显示状态

[yw0903]

//关闭事件
function ClosedMenu(obj,oobj)
{
obj.style.display="none";
oobj.style.display="none";
}

以上代码，如何加入一段Cookie.用来保存点击后的层的显示状态
点击后关闭层，刷新也不显示。只在重新打开页面或者清空Cookie后显示。
JS刚刚入门，还请各位多多指教。谢谢了！

[yw0903]

//关闭事件
function ClosedMenu(obj,oobj)
{
obj.style.display="none";
oobj.style.display="none";
}

还有不解的地方。
为什么加入alert(obj);后弹出的对话框显示的[object]，而不是我传入层的id值。

[yw0903]

//关闭事件
function ClosedMenu(obj,oobj)
{
obj.style.display="none";
oobj.style.display="none";
}

还有不解的地方。
为什么加入alert(obj);后弹出的对话框显示的[object]，而不是我传入层的id值。

[varlj]

alert(obj.id)

[yw0903]

太谢谢了。

[zero8500]

学习

[varlj]

function SetCookie(name,value)
{
    var Days = 30; 
    var exp  = new Date();
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)    
{
    var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
     if(arr != null) return unescape(arr[2]); return null;

}
function ClosedMenu(obj,oobj)
{
    obj.style.display="none";
    oobj.style.display="none";
    SetCookie("obj","none");
    SetCookie("oojb","none");
}

//启动的时候
function start()
{
    var s1 = getCookie("obj");
    var s2 = getCookie("oojb");
    if(s1!=null)
        obj.style.display=s1;
    if(s2!=null)
        oobj.style.display=s2;
}

[nj_link]

//一个例子：

<script>document.write("<center><b>来访统计,cookies的运用</b>")</script>
<script>document.write("</center><p>")</script>
<script language="JavaScript">
<!--
var caution = false
function setCookie(name, value, expires, path, domain, secure) {
var curCookie = name + "=" + escape(value) +
((expires) ? "; expires=" + expires.toGMTString() : "") +
((path) ? "; path=" + path : "") +
((domain) ? "; domain=" + domain : "") +
((secure) ? "; secure" : "")
if (!caution || (name + "=" + escape(value)).length <= 4000)
document.cookie = curCookie
else
if (confirm("Cookie exceeds 4KB and will be cut!"))
document.cookie = curCookie
}
function getCookie(name) {
var prefix = name + "="
var cookieStartIndex = document.cookie.indexOf(prefix)
if (cookieStartIndex == -1)
return null
var cookieEndIndex = document.cookie.indexOf(";", cookieStartIndex + prefix.length)
if (cookieEndIndex == -1)
cookieEndIndex = document.cookie.length
return unescape(document.cookie.substring(cookieStartIndex + prefix.length, cookieEndIndex))
}
function deleteCookie(name, path, domain) {
if (getCookie(name)) {
document.cookie = name + "=" +
((path) ? "; path=" + path : "") +
((domain) ? "; domain=" + domain : "") +
"; expires=Thu, 01-Jan-70 00:00:01 GMT"
}
}
function fixDate(date) {
var base = new Date(0)
var skew = base.getTime()
if (skew > 0)
date.setTime(date.getTime() - skew)
}
var now = new Date()
fixDate(now)
now.setTime(now.getTime() + 365 * 24 * 60 * 60 * 1000)
var visits = getCookie("counter")
if (!visits)
visits = 1
else
visits = parseInt(visits) + 1
setCookie("counter", visits, now)
document.write("欢迎您的第" + visits + "次光临！")
// -->
</script>