let txt = "";
    let bytes = fnUtil_stringToBytes(txt)
    let txt2 = fnUtil_bytesToString(bytes)
    let base64 = fnUtil_bytesToBase64(bytes)

    let byts2=fnUtil_base64ToBytes(base64)
    let txt3= fnUtil_base64ToString(base64)
    console.log("生成随机数：", fnUtil_randInt())