jQuery Ajax响应200,但无法访问响应数据

在没有jQuery的情况下,我如何在纯javascript中做到这一点?

$.ajax({
    url:'https://poloniex.com/private.php?currencyPair=BTC_LTC&rate=0.016&amount=1&command=buy', 
   dataType:'json',
   success: function(data, textStatus, xhr){
console.log('asdfasdfadsf');     
console.log(data);
     console.log('hello' + textStatus);
     console.log(xhr.responseText);

   }//success

}); //ajax