Event listeners on plugin in document.onload events in Opera

I am trying to understand an issue where event-listener registration on plugins doesn't work in Opera unless I delay them.

In particular, this doesn't work:

document.onload = function() {
    plugin.addEventListener("foo", function() { alert('onFoo'); }, false);
}

while delaying the addEventListener() cal开发者_如何学Pythonl somewhat through e.g. an alert() does:

document.onload = function() {
    alert('onload()');
    plugin.addEventListener("foo", function() { alert('onFoo'); }, false);
}

It seems that plugins are only loaded after document.onload.

As a non-web-developer, am I missing something simple here? Or is this a known Opera problem with a common work-around?

in general the timing of plugin initialisation, script execution and document event handling isn't well specified, meaning browsers are likely to do different things.

In this case it sounds like you need to make sure the plugin is initialised before you add the listener. One way to do that would be to check for a property the plugin will define (for example, if it was a Flash plugin you could check if PercentLoaded was defined to see if it is ready for scripting.) If not ready for scripting, you could use a timeout to try again a little bit later.

At Opera we've been trying to align with the majority of the other browsers in this area recently, and Opera 10.50 may be working better for you. I'm not sure if we have things fully under control yet though - it would be interesting to hear from you whether behaviour changed in 10.50.

We have further improved handling of this in Opera 10.60, so that behavior is much closer to the other browsers wrt. plug-in initialization and script readyness. I believe the original approach should work now.

I don't know much about Opera but have you tried using jquery's ready function? It's purpose is to add a function you want executed once the DOM is fully loaded and it should work cross browser.

$(document).ready(function() {
 plugin.addEventListener("foo", function() { alert('onFoo'); }, false);
});

More info about the ready function can be found here