Detect if Flash application loaded correctly using Javascript?

Question

My product opens a web browser and points it at an HTML file containing a local Flash application. How do I detect programmatically whether this file loaded successfully and

Answer 1

Actually, when the HTML page finishes loading, the Flash content may not be completely loaded yet. If the SWF isn't done loading, then it will appear to have failed.

The method I usually recommend is to have the SWF call a JavaScript function through ExternalInterface right away when the document class constructor is invoked. Basically, assume that the SWF has failed to load unless that JS function is called.

Answer 2

Answering my own question: https://sourceforge.net/forum/message.php?msg_id=5929756

1. Define a Javascript function that should be invoked if Flash loaded.
2. Invoke this method from the top of your Flash file.
3. Use a timer to detect if the callback is never invoked.
4. Prefer invoking Javascript functions from Flash rather than invoking Flash functions from Javascript. Either way you cannot invoke a function that has not been loaded yet. It is far easier to guarantee that the browser has finished loading your Javascript function before invoking it from Flash, than guaranteeing that Flash finished loading your Flash function before invoking it from Javascript.

Here is an example:

• I am using swfobject to embed Flash.
• I use FlashVars to tell Flash which Javascript function to invoke. This is useful if there are multiple Flash objects on the page.

Flash

var params:Object = LoaderInfo(this.root.loaderInfo).parameters;
if (ExternalInterface.available)
{
    var onLoaded:String = params["onLoaded"];
    if (onLoaded != null)
        ExternalInterface.call(onLoaded, true);
}

Javascript

var flashLoaded = false;
var flashTimer;

function onFlashLoaded()
{
    flashLoaded = true;
    clearTimeout(flashTimer);
}

function onFlashTimeout()
{
    if (!isFlashLoaded)
    {
        // Remove the Flash object in case it is partially loaded
        $("#videoFeed").empty();
        $("#videoFeed").append('<div id="flashObject"></div>');
        alert("Failed to load video player");
    }
    clearTimeout(flashTimer);
}

function connectToVideo()
{
    var flashvars = {};
    flashvars.onLoaded = "onFlashLoaded";

    var params = {};
    params.menu = false;

    var attributes = {};

    isFlashLoaded = false;
    flashTimer = setTimeout("onFlashTimeout()", 5000);

    swfobject.embedSWF("flash/VideoFeed.swf", "flashObject", "800", "600", "11", "expressInstall.swf", flashvars, params, attributes);
}

Answer 3

Acording to adobe ExternalInterface documentation: http://livedocs.adobe.com/flex/3/langref/flash/external/ExternalInterface.html some web browsers restrict calling a Javascript function through ExternalInterface in the document class constructor if a pop-blocker is enabled.

Are there any other solution to detect when the swf movie has been successfully loaded?

Answer 4

In cases where you cannot modify the swf and adding an ExternalInterface is not an option, you can still use Javascript to get the status of the swf. For example, you can call document.getElementById(swf_id).PercentLoaded() from Javascript, and wait for it to be 100.

That won't tell you what exception was thrown if the swf failed to load, but at least you will know for sure whether it loaded. Other useful calls are found here: http://www.adobe.com/support/flash/publishexport/scriptingwithflash/scriptingwithflash_03.html