I apologise in advance if this post is something you've heard a million times already or seems like a trolling attempt. I just want some advice and I'm coming up short with my own Google searches.

Basically, I would like to start learning some game development in my own free time (nothing serious, just purely as a hobbyist for fun). I'd like to know what the communities opinions are on the old HTML5/Javascript v Flash argument but purely from a game development perspective. I know people say Flash is dying because of issues like SEO, memory/bandwidth usage and Apple dropping it on tablet and mobile devices, so is it worth me dedicating my free time to learning to use Flash/AS3 for game development or should I focus on HTML5/Javascript?

At the moment, I'm not sure HTML5/Javascript is mature enough or has the support tools that Flash does (framework, IDE, etc) and there seems to be a lot more resources online for beginner Flash/AS3 programming. When I'm reading tutorials online for Flash/AS3 I always have it in the back of my head that I'm wasting my time because it won't be around in a few years and I should be investing that time learning HTML5/Javascript.

Thoughts?

Disclaimer: I'm not trying to spark a flame war or troll anyone - I believe in the right tools for the job and I don't want to waste my time learning something that won't be around in a few years.