I'm creating an mobile app with mainly Html5 and got curious about the possibility for people to view the code behind their mobile app? is it possible? in that case, is it easy done? Thanks!
What you're talking about is decompiling. For Android, at least, it isn't necessarily difficult under the right circumstances, but if the developer is at all concerned about security they've hopefully obfuscated their code to make the process much more difficult if not impossible for the average person. There are plenty of resources online with instructions on how this can be done but it is often a pretty sketchy thing to do. If the process is interesting that's one thing, but don't jack other people's code. The process is much more complicated for iOS since Apple tries to lock our code down with DRM. It is, however, still technically possible – typically with a 3rd party app to crack it and a jailbroken iOS device.