You are allowed to do much more with the language because it does not have a "compiler" or types. There are some great frameworks out there like ExtJS and jQuery that try and simplify things for you, but even with them, you are really allowed to do an amazing amount of damage if you want to. 2) ActionScript is much more confining and hence, much easier to maintain. Adobe did a lot of work to keep you out of the difficult parts of ECMAScript. Extensions. Modify and extend Mozilla applications Add-ons add new functionality to Gecko-based applications such as Firefox, SeaMonkey, and Thunderbird.
There are two main types of add-on: Extensions add new features to the application, while Themes modify the application's user interface. For both extensions and themes, Mozilla operates a repository at addons.mozilla.org, also known as AMO. When you submit add-ons to AMO they are reviewed, and after passing review they are made available to users. You don't have to submit add-ons to AMO, but if you do, users can take confidence in the fact that they have been reviewed, and you can benefit from AMO's visibility as a source for useful add-ons.
They are currently written with mostly Firefox in mind, but most if not all should easily translate to SeaMonkey, Thunderbird or any of the other applications. For Thunderbird, you may also find the extension HowTo or FAQ pages helpful. If you're looking for a place to get started, try our tutorial, Building an Extension or MozillaZine's Getting started tutorial. Use the Extension Wizard to generate a template to start with. Be sure to set the development preferences. Building an Extension. Introduction This tutorial will take you through the steps required to build a very basic extension - one which adds a status bar panel to the Firefox browser containing the text "Hello, World!
". Note: The extension created by this tutorial won't work in Firefox versions that don't have a static status bar (that is, Firefox 4 and up). You can find a more up-to-date tutorial in the XUL School tutorial The Essentials of an Extension. Since Firefox 4 (and other Mozilla 2 based applications) there are two types of extensions: Traditional, classic, or XUL extensions are more powerful, but more complicated to build and require a restart to install.
This article explains how to build a traditional extension for Firefox. For a tutorial on building an extension for Thunderbird, see Building a Thunderbird extension. Quick Start A Hello World extension similar to what you can generate with the Extension Wizard is explained line-by-line in another tutorial from MozillaZine Knowledge Base. <? XUL Overlays.