Why is audio.duration different in FF and chrome?

Question

JavaScript

var  audio = document.getElementById("player");
...
$('#player').attr('src', 'path/to/audio.mp3');
...
audio.addEventListener("loadeddata", function () {
        var duration = audio.duration;
        console.log (duration );
    });

chrome:

Fifefox:

Chrome shows the correct duration. what's the matter?

Answer 1

Better use "canplaythrough". Usually "loadeddata" fires too soon.