Editing Cross-platform software (section)

===Approaches <span class="anchor" id="Approaches to cross-platform programming"></span> ===
There are different ways to write a cross-platform application. One approach is to create multiple versions of the same software in different ''source trees''—in other words, the Microsoft Windows version of an application might have one set of source code files and the [[Apple Macintosh|Macintosh]] version another, while a [[Free and open-source software|FOSS]] [[*nix]] system might have a third. While this is straightforward, compared to developing for only one platform it can cost much more to pay a larger team or release products more slowly. It can also result in more bugs to be tracked and fixed.

Another approach is to use software that hides the differences between the platforms. This [[abstraction layer]] insulates the application from the platform. Such applications are ''platform agnostic''. Applications that run on the JVM are built this way.

Some applications mix various methods of cross-platform programming to create the final application. An example is the Firefox web browser, which uses abstraction to build some of the lower-level components, with separate source subtrees for implementing platform-specific features (like the GUI), and the implementation of more than one scripting language to ease [[software portability]]. Firefox implements [[XUL]], [[CSS]] and JavaScript for extending the browser, in addition to classic [[Netscape]]-style browser plugins. Much of the browser itself is written in XUL, CSS, and JavaScript.