js 对utf-8进行base64解码

后端加密，前端解密

后端加密方法（C#）

 public static string Base64Encode(string source)
        {
            return Base64Encode(Encoding.UTF8, source);
        }

        /// <summary>
        /// Base64加密
        /// </summary>
        /// <param name="encodeType">加密采用的编码方式</param>
        /// <param name="source">待加密的明文</param>
        /// <returns></returns>
        public static string Base64Encode(Encoding encodeType, string source)
        {
            string encode = string.Empty;
            byte[] bytes = encodeType.GetBytes(source);
            try
            {
                encode = Convert.ToBase64String(bytes);
            }
            catch
            {
                encode = source;
            }
            return encode;
        }

前端解密

   function atou(str) {
        return decodeURIComponent(escape(window.atob(str)));
    }