js 添加、获取、删除 cookie

// 保存 Cookie
function setCookie(name, value) {
    expires = new Date();
    expires.setTime(expires.getTime() + (1000 * 86400 * 365));
    document.cookie = name + "=" + escape(value) + ";";
}
// 获取 Cookie
function getCookie(name) {
    cookie_name = name + "=";
    cookie_length = document.cookie.length;
    cookie_begin = 0;
    while (cookie_begin < cookie_length) {
        value_begin = cookie_begin + cookie_name.length;
        if (document.cookie.substring(cookie_begin, value_begin) == cookie_name) {
            var value_end = document.cookie.indexOf(";", value_begin);
            if (value_end == -1) {
                value_end = cookie_length;
            }
            return unescape(document.cookie.substring(value_begin, value_end));
        }
        cookie_begin = document.cookie.indexOf(" ", cookie_begin) + 1;
        if (cookie_begin == 0) {
            break;
        }
    }
    return null;
}
// 清除 Cookie
function delCookie(name) {
    var expireNow = new Date();
    document.cookie = name + "=" + "; expires="+expireNow+"" + "; path=/";
}