//----------------------------
//
//     读写cookie
//
//----------------------------


function GetCookieVal(offset)
//获得Cookie解码后的值
{
    var endstr = document.cookie.indexOf(";", offset);
    if (endstr == -1)
        endstr = document.cookie.length;
    return unescape(document.cookie.substring(offset, endstr));
}

function SetCookie(name, value)
//设定Cookie值
{
    var expdate = new Date();
    var argv = SetCookie.arguments;
    var argc = SetCookie.arguments.length;
    var expires = (argc > 2) ? argv[2] : null;
    var path = (argc > 3) ? argv[3] : "/";//路径设置为/，可以使得各页面共享cookie
    var domain = (argc > 4) ? argv[4] : null;
    var secure = (argc > 5) ? argv[5] : false;
    if (expires != null) expdate.setTime(expdate.getTime() + (expires * 1000));
    document.cookie = name + "=" + escape(value) + ((expires == null) ? "" : ("; expires=" + expdate.toGMTString()))
+ ((path == null) ? "" : ("; path=" + path)) + ((domain == null) ? "" : ("; domain=" + domain))
+ ((secure == true) ? "; secure" : "");
}

function DelCookie(name)
//删除Cookie
{
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval = GetCookie(name);
    document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString();
}

function GetCookie(name)
//获得Cookie的原始值
{
    var arg = name + "=";
    var alen = arg.length;
    var clen = document.cookie.length;
    var i = 0;
    while (i < clen) {
        var j = i + alen;
        if (document.cookie.substring(i, j) == arg)
            return GetCookieVal(j);
        i = document.cookie.indexOf(" ", i) + 1;
        if (i == 0) break;
    }
    return null;
}