The advantages of cross-platform development are clear: you can write one application and run it on several platforms. Instead of having several applications in various languages, you are able to save a lot of code and expense. The fewer code and languages you use the fewer your bugs, distribution and maintenance effort.
I wanted to see how easy it would be to support several platforms with a single language and environment. For this, I chose JavaScript which is gaining more and more impact every day and runs nearly everywhere. I will show you which frameworks I used and how cross-platform development with JavaScript could look like on the basis of some examples.