HTML 5 Video. Returning playback error with source element instead of attr

error-handling, html, javascript, video

Solution

If sources are involved, errors in loading sources must be caught from the `<source>` elements themselves. However, to check if all of the `<source>` elements failed, check the `<video>` element's `networkState` property if it's `NETWORK_NO_SOURCE`.

More details on the following here:

- HTMLMediaElement

- `<source>`

- Using HTML5 audio and video

Here's a sample code when the first source fails to load and outputs an error into the console:

HTML

<video id="b" autoplay controls poster="http://img.rasset.ie/000736d2-512.jpg" width="620" height="400">
    <source src="tgif.vid" />
    <source src="http://html5doctor.com/demos/video-canvas-magic/video.mp4" />
    <source src="http://html5doctor.com/demos/video-canvas-magic/video.webm" />
    <source src="http://html5doctor.com/demos/video-canvas-magic/video.ogg" />
</video>

JS (using handlers to avoid inine scripts)

var sources = document.getElementsByTagName('source'),
    i;

for (i = 0; i < sources.length; i++) {
    (function (i) {
        sources[i].addEventListener('error', function (e) {
            console.log('Error loading: '+e.target.src);
        });
    }(i));
}

Problem

I'm looking to add some error handling to a simple HTML5 video element. Im using this chunk of code which appears everywhere online: JS ``` function playbackFailed(e) { // video playback failed - show a message saying why switch (e.target.error.code) { case e.target.error.MEDIA_ERR_ABORTED: alert('You aborted the video playback.'); break; case e.target.error.MEDIA_ERR_NETWORK: alert('A network error caused the video download to fail part-way.'); break; case e.target.error.MEDIA_ERR_DECODE: alert('The video playback was aborted due to a corruption problem or because the video used features your browser did not support.'); break; case e.target.error.MEDIA_ERR_SRC_NOT_SUPPORTED: alert('The video could not be loaded, either because the server or network failed or because the format is not supported.'); break; default: alert('An unknown error occurred.'); break; } } ``` HTML ``` <video id="a" src="tgif.vid" autoplay controls onerror="playbackFailed(event)" poster="http://img.rasset.ie/000736d2-512.jpg" width="620" height="400"></video> ``` Above works fine and I get a snappy alert box when the page loads. However if i dont have a "src" attribute and instead use the `<source>` tag within the `<video>` element "onerror(event)" doesn't fire? Example markup: ``` <video id="b" autoplay controls onerror="playbackFailed(event)" poster="http://img.rasset.ie/000736d2-512.jpg" width="620" height="400"> <source src="tgif.vid"> </video> ``` Note I've given both videos elements above the ids "a" and "b". Can someone explain why in the following code: ``` <script> var a = document.getElementById('a'); var b = document.getElementById('b'); a.addEventListener('error', function(e){alert('error event on a')}); b.addEventListener('error', function(e){alert('error event on b')}); </script> ``` I only get an alert for "a" and not "b" I need to use the `<source>` tag as I'll have multiple media type for different devices etc. Thanks in advance for any answers / comments S

Original source