Even though the question is kind of ambiguous and could be construed as flamebait by some, I'll answer it in good faith.
HTML 5 won't be standardized till 2022. And you still have to deal with the browser rendering differences that may arise "just because". Everyone is foretelling the death of Flash, and while there may be issues, how many platforms that have reached Flash's level of user and developer adoption and then up and died ? For crying out loud, PHP is still around still terrorizing server racks even in the presence of other scirpting languages (Ruby, Python ...).
Other comments come to my mind. In the IT world, the phrase 'I only know x' is a career limitation regardless what 'x' is. Languages, databases, frameworks, platforms, etc. all wax and wane as fashion and technology change over time. In this business, if you aren't learning something new, you are going to be out of a job sometime in the future. If you don't like change, or don't like learning new things, then you probably should reevaluate your career choice anyway. This isn't a business where you learn how to install nut 'z' onto bolt 'a' and then do that for the rest of your life.
I see your point Mark, but the idea that someone could learn one tech and be successfull long term wasn't what I was trying to get across. In the IT field, you generally can't help but become versed in multiple technologies since the technology stacks on most applications are huge. For instance, I am working on a pet project and before I can even get a simple proof-of-concept going I have to wade through Flex, Hibernate, MySQL, Sql, ANT, Java and its "jar hell", Eclipse, Git and soon Jenkins.
On a side note, I intend to check out HTML 5/JS especially since Adobe Edge was released at a price point that falls in line with my other technologies. What I was saying is that there is a whole lot of fanboyism in the field, and some of it concerns the demise of Flash and I have yet to see any technology that has completely hit the pavement even when it probably should have.
I think you and I are on the same page, my comments weren't directed at your reply, my comments were directed at the original posters comment of 'I only know flex'. Should he/she learn HTML5? Absolutely! If you plan to be working in the 'web' space, you are going to need to know HTML5. Does needing to learn HTML5 mean that flex is dead? Absolutely not! That idea is based on a flawed world view of 'I should only need to know one thing', which has never been true in IT, and frankly, isn't true for almost any career/aspect of life.
The whole premise that 'x is now here, so y must be dead' is just stupid. The main database I use has been declared dead by pundits for 30 years, and yet the majority of healthcare systems, and many huge banking systems still use it every day. Now it is seeing some renewed general interest with the rise of 'noSQL' databases. Keep those wide ties, guys - they'll be back in fashion before you know it.
Your "friends" are biased. Run away fast. And google for the other threads in this forum on the topic. It's not all gloom and doom, despite what the anti-Flash crowd wants people to think.
Besides, the new Flex roadmap just released has:
Falcon JS compiler contribution to Apache
While it's not ready for prime time yet (sounds just like HTML5 huh?), this hardly impiles the Flex SDK will be "dead" any time soon. Your friends have no idea what they're talking about.
. my friends are very clear. me too.
Flex will be replaced by HTML5. But HTML5 will take more time to reach flex's standard.
To do a simple task in HTML5,i have to spent much time in research. Most browsers still not support HTML5, particularly IE 9.
Those who develope regular website, can go with HTML5. But some devlopers like me, developing very large applications. Iit will take more than 1.5 years to complete our code. So we should have robust language.
HTML5 surely not at this time. We never run our application in mobile or any small devices. I can survive with flex more than 3 years without even a single update.
Adobe already did that much for Flex.
Whoever think 'HTML5 or FLEX', just analyze your project requirement then choose your technology.
I am with Flex 4.6 now.