JS Cookie相关操作

function setCookie(cookieName, cookieValue, expires) { // 设置Cookie

    function getCookieName(cookieName) { //获取并返回与 cookieName 同名的 cookie 名称，允许大小写不同,如果不存在这样的 cookie，就返回 cookieName
        var lowerCookieName = cookieName.toLowerCase(); //转换为小写
        var cookieStr = document.cookie; // 获取当前cookie
        if (cookieStr == "") {
            return cookieName;
        }

        var cookieArr = cookieStr.split(";");
        var pos = -1;
        for (var i = 0; i < cookieStr.length; i++) {
            pos = cookieArr[i].indexOf("=");
            if (pos > 0) {
                if (cookieArr[i].substring(0, pos).toLowerCase() == lowerCookieName) {
                    return cookieArr[i].substring(0, pos);
                }
            }
        }
        return cookieName;
    }

    function writeCookie(cookieName, cookieValue, expires) { // 写cookie,不区分大小写
        if (expires) {
            document.cookie = getCookieName(cookieName) + "=" + escape(cookieValue) + "; expires=" + expires.toGMTString();
        } else {
            document.cookie = getCookieName(cookieName) + "=" + escape(cookieValue);
        }
    }

    function readCookie(cookieName, defaultValue) { //获取并返回 cookie 值,不区分大小写
        var lowerCookieName = cookieName.toLowerCase();
        var cookieStr = document.cookie;

        if (cookieStr == "") {
            return defaultValue;
        }

        var cookieArr = cookieStr.split("; ");
        var pos = -1;
        for (var i = 0; i < cookieArr.length; i++) {
            pos = cookieArr[i].indexOf("=");
            if (pos > 0) {
                if (cookieArr[i].substring(0, pos).toLowerCase() == lowerCookieName) {
                    return unescape(cookieArr[i].substring(pos + 1, cookieArr[i].length));
                }
            }
        }

        return defaultValue;
    }

    writeCookie(cookieName, cookieValue, expires);
}