Question

I have a web app in http://domain1/app1/called.html, and I want to embed that application inside http://domain2/app2/caller.html with an iframe (or a popup, it’s the same)

the user should be able to interact with called.html, until they press a certain button, in that case I need to tell caller.html that the user selected an item from called.html

I tried implementing it with javascript.

in called.html I encode the data in json, and then I execute a “called_callback” javascript function in caller.html, passing the json as a parameter.

if called.html was called with a popup, I issue window.opener.called_callback( jsonData ), if it’s an iframe I just issue parent.called_callback( jsonData )

having caller.html and called.html in the same domain everything works fine, but from different domains I get the following errors:

permission denied (on IE6)

and

Unsafe JavaScript attempt to access frame with URL [..]/caller.html from frame with URL [...]called.html. Domains, protocols and ports must match. (on google chrome)

Is it possible to overcome this limitation?

What other way of achieving it can you think of???

I guess caller.html could implement a web service, and I could send the result calling it, but the page caller.html would have to poll in order to detect any change…

So how can one application communicate with another one in a different domain to signal an event???

Answer 1

Thanks to both answer I found the following:

http://benalman.com/code/projects/jquery-postmessage/docs/files/jquery-ba-postmessage-js.html

http://benalman.com/projects/jquery-postmessage-plugin/

jQuery postMessage enables simple and
easy window.postMessage communication
in browsers that support it (FF3,
Safari 4, IE8), while falling back to
a document.location.hash communication
method for all other browsers (IE6,
IE7, Opera).

With the addition of the
window.postMessage method, JavaScript
finally has a fantastic means for
cross-domain frame communication.
Unfortunately, this method isn’t
supported in all browsers. One example
where this plugin is useful is when a
child Iframe needs to tell its parent
that its contents have resized.

I’ll have a look at it…