XMLHttpRequest始终返回未定义

Question

I am making an XMLHttpRequest that should return an mp3 file. However, it returns ' undefined '. I am not getting any errors in the console (thought it would be a allow-content issue but this is a public API).

This is the jssfiddle and the code. Please note that I am not posting a valid API key so we should receive " ERROR: The API key is not available! " instead of the mp3, but still not an undefined .

https://jsfiddle.net/r0j9yojo/5/

<button onclick="doit()">doit</button>

function doit() {
    var endpoint = 'https://api.voicerss.org/?key=testkey&src=test&hl=es-es';
    var client = new XMLHttpRequest();
    client.open('GET', endpoint, true);
    client.onreadystatechange = function() {
      if (client.readyState == 4 && client.status == 200) {
    alert(client.readyState + '/' + client.status + '/' + client.responsetext);
      }
    }
    client.send();
}

Answer 1

The property of client you are looking for is responseText , not responsetext (note the capitalized T).

In the future, use console.log(object) (in your case console.log(client) ) to inspect an object through your browsers console, which is usually accessed with F12 or through the menu.