function main (){
    $.CTA("BTC_USDT", function(st){
        var r = st.records; //获取K线数组
        if (r.Length <20) return; // 过滤K线长度
        var close = r[r.length - 2].close; //获取上根K线收盘价
        var mp = st. positLon.amount; //获取持仓信息

        var boll = TA.BOLL(r, 20, 2); // 计算布林带指标
        var upLine = boll[0];
        //获取上轨数组
        var midLine = boll[1]; //获取中轨数组
        var downLine = boll[2];//获取下轨数组