As it is widely known, AJAX Requests are only possible if port, protocol and domain of sender and receiver are equal. [...] Having this cleared out, we will cover ways around this restriction.

He covers three main approaches to allowing these cross-domain requests (and some of the security implications that can come with them):

• CORS (Cross Origin Resource Sharing)
• JSONP (Javascript with a local domain callback)
• Iframes

He also briefly mentions things like window.postMessage (HTML5) and the use of a backend script to proxy a request into your application's local code.

We are proud to present our first ever tutorial, aimed at helping Zend Framework developers to integrate their iframe applications into Facebook using the new(ish) OAuth for Canvas authentication mechanism. This is the first part in a three part series aimed at building a fully working Facebook Iframe application using the Zend Framework.

The tutorial is posted in a downloadable PDF to you can take it anywhere your code goes for easier reference.

The new Facebook API has already spread over the application developers and if you're like me, you've already got your hands dirty to see how this new thing works. If you have tried to follow the documentation to authorize/get session in your canvas application, it is likely you have already hit roadblocks. Well, I am no savior but I have glued together a few clues and got it working for myself.

He walks you through the three simple steps: getting the new API, setting ip a correct configuration file and creating a sample "main page" for your application that echoes out a "Hello World" sort of message to each visitor.

This article contains example application (trivial file-sharing service, like rapidshare, megaupload or yousendit) which uses embedded frames (IFRAME) to upload file. While file is uploaded to hidden frame, user can still access web-page and fill "file description" field.

They talk briefly about the PHP functions that will be used in the tutorial and the concept of using IFRAMEs to handle the content coming in (without reloading the page). The rest of the article is a code dump showing the pieces of (procedural) code to get the job done. There's some commenting, but if you're a new coder to PHP, you might want to check out the main PHP site for some more information on the functions used.