With HTML 5’s emphasis on web application development, there’s plenty of new features for developers to use, some of which we can use today:

• A 2D drawing API for scripting graphics using the new canvas element, which is supported in all the major browsers except for Internet Explorer.
• registerProtocolHandler and registerContentHandler, which allow web applications to register for certain protocols or MIME types. Both are available in Firefox.
• A manifest caching mechanism to support offline web applications, available in Firefox and Safari.
• Video and audio APIs. The majority of the API works in Firefox, Opera (experimental build), and Safari—although Safari only uses Apple’s proprietary .mov format, rather than the open-source Ogg formats supported by Firefox and Opera.
• window.postMessage: cross-document messaging implemented in all major browsers.
• history.pushState to enable better back-button support in Ajax apps. (No implementations yet, but window.onhashchange is supported in IE8.)
• A drag and drop API with a draggable attribute, supported in Firefox 3.5.
• An editing API that hooks into the contenteditable attribute allowed on any element, already in all major browsers.
• Client-side persistent storage using key/value pairs and support for embedded SQL databases: key/value pairs are in Firefox, Safari, and IE8, while SQL is supported only in Safari at this point.

For more read the full SitePoint article

Let’s we are building a dynamic photo gallery in flash using ActionsScript 3.0. The data is originally placed in a MySQL database, and through a web application written in PHP, the user is allowed to upload files to the gallery or delete existing files. Flash is used as a front-end in order to achieve better results for visual effects. When the user makes changes to the gallery, the PHP application updates the XML file located on the webserver with the new data. When accesing the page containing the flash galley, the user should see the updated gallery, but instead he sees the old one. The reason is that the browser loads the XML file from it’s cache and not the webserver. Not even a refresh won’t solve this problem on most browsers.

The solution is a small trick used by programmers to fool the browser into thinking it is always loading a different file, by adding an extra parameter (with a ramndom value)  to the URL of the file that is beeing loaded. So, even if the file name itself is the same, the URL changes on every request.

The changes must be made on the portion of the code where the XML file is requested throught ActionScript.

myIdentifier=Math.round(Math.random()*10000);
xmlData.load("gallery.xml?uid="+myIdentifier);

Simple as that!