Javascript XMLHttpRequest在IE 9上不起作用

Question

I did this script that works on IE10 and above. It also works on Opera, Chrome, Firefox.

function trackid() {
    var client = new XMLHttpRequest();
    client.open('GET', 'https://radio.riddimdub.com/playing.txt');
    client.onreadystatechange = function() {
        var trackName = client.responseText;
        document.getElementsByClassName("tracktitle")[0].innerHTML = trackName;
    };
    client.send()
};
trackid();
setInterval(trackid, 5000);

Now I changed it a little bit to make it work for IE9. I did this:

function trackid() {
    var client = new XMLHttpRequest();
    client.open('GET', 'https://radio.riddimdub.com/playing.txt');
    client.send()
    if (client.readyState === client.DONE) {
        var trackName = client.responseText;
        document.getElementsByClassName("tracktitle")[0].innerHTML = trackName;
    }
};
trackid();
setInterval(trackid, 5000);

The problem is that I get no error in Console on IE9, nor on Opera but it doesn't work on both.

Is worth to mention that I've also tried with:

try {
} finally {
}

Is there anything I did wrong?

Answer 1

I did it. Thanks for the info guys. Here's how:

function trackid() {
    var client = new XMLHttpRequest();
    client.open('GET', 'https://radio.riddimdub.com/playing.txt');
    client.onreadystatechange = function() {
        if (client.readyState === client.DONE) {
            var trackName = client.responseText;
            document.getElementsByClassName("tracktitle")[0].innerHTML = trackName;
        }
    }
    client.send()
};
trackid();
setInterval(trackid, 5000);