What is Chrome?
In a nutshell, Chrome is the user interface of Mozilla products. The user interface is composed mostly of XUL, XBL, CSS, and JS files. Extensions are (usually) chrome applets. 90% of an extension, typically is chrome.
In the XUL world, Chrome is the top level window which contains groups of UI elements of various types. Example of chrome are the browser window and dialog window. The chrome obtains its UI description from four types of providers:
- Content provider
- Provides the skeleton, i.e., the menus, command buttons
- Skin provider
- Supplies the look-and-feel of the chrome
- Platform provider
- Gives platform dependent UI description
- Locale provider
- Offers the language and culture sensitive resources
Chrome in depth
Chrome URLs
To maximize the flexibility, Mozilla introduces a new technology called "Configurable Chrome". A XUL file can be written in such a fashion that its chrome description comes from a mixture of physical sources, either locally, remotely, or a combination of both. An end user may customize her/his configuration to pick up any of the source type from his favor chrome providers.
To achieve this, chrome type URLs must be used to reference external sources; such as CSS files and JavaScript files. The general form of chrome URLs look like this:
chrome://WindowType/ProviderType/[ProviderName/]
What you can do with Chrome
Here are the following examples of what you can do with Chrome: