获取Cookie 

function GetCookie(cookieName) {

    var cookieString = document.cookie;

    var start = cookieString.indexOf(cookieName + '='); // 加上等号的原因是避免在某些 Cookie 的值里有 与 cookieName 一样的字符串。

    if (start == -1) return null; // 找不到 

    start += cookieName.length + 1;

    var end = cookieString.indexOf(';', start);

    if (end == -1) return unescape(cookieString.substring(start));

    return unescape(cookieString.substring(start, end));

}

设置cookie

function SetCookie(name, value) {

    var argv = SetCookie.arguments;

    var argc = SetCookie.arguments.length;

    var expires = (argc > 2 && argv[2] != null) ? argv[2].toGMTString() : null;

    var path = (argc > 3 && argv[3] != null) ? argv[3] : '/';

    var domain = (argc > 4 && argv[4] != null) ? argv[4] : null;

    var secure = (argc > 5 && argv[5] != null) ? argv[5] : false;

    var content = name + "=" + escape(value) + ";";

    if (expires != null) { content += " expires=" + expires + ";"; }

    if (path != null) { content += " path=" + path + ";"; }

    if (domain != null) { content += " domain=" + domain + ";"; }

    if (secure) { content += " secure;" }

    document.cookie = content;

}