Cross-platform apps are wonderful. Having the ability to create an app and have it run on multiple operating systems is ideal for developers. After all, it increases the audience for their work. Ultimately, for a paid app, this equates to more money. More money is good, right? Right.

However, it is not typical for the owner of the operating system to help developers move apps to other platforms. Exclusivity of an app can drive sales of the platform. In other words, if all apps ran on all platforms, the platform really would not matter to consumers. With that said, Microsoft does something shocking, as it shows off how easy it is to create one app using WinJS that runs on Windows 8.1, Windows Phone 8.1 and FireFox OS. Are pigs flying?

"Starting with Windows Phone 8.1, it is now possible to use the Windows Runtime to build apps that can target each form factor in the family of Windows devices. Using the universal Windows app project templates, you can now create one app where your business logic can be surfaced up through a user experience relevant to the device. This unified approach to app development means that your app has the potential to reach not just Windows phones and tablets, but Windows laptops and workstations as well", says Doris Chen.

Chen further explains, "with the open sourcing of WinJS, it might be interesting to see if we can build an app that runs across phone, Windows and another platform such as Firefox OS. Martin Beeby did an interesting demo on building a JavaScript app and see how far we can take it".

Whoa, whoa, whoa, stop the clock! Microsoft using WinJS to create a Javascript App that will run on Firefox OS? This is huge. For one, it gains the company major geek credibility for making WinJS open-source in the first place. But Microsoft creating an app for Firefox OS? That's turning the cool-factor up to eleven.

As you can see in the below video, the developer, Martin Beeby, creates a relatively rudimentary app for accessing Flickr on Windows and Windows Phone 8.1. However, it is extremely impressive to see that same app run on Firefox OS with almost no effort. While it is doubtful that Microsoft will become a full-fledged Firefox OS developer, this demo shows how awesome WinJS really is.

Strangely, Firefox is embracing closed-source, as Microsoft dabbles in open-source. What is this, Bizarro World?

Image Credit: Tyler Olson/Shutterstock