Why is it acceptable to expect that Flash will be available/enabled, but not JavaScript?_问答_开发者

It doesn't take long when surfing the web to observe the general co开发者_Python百科nsensus that Flash is an expected standard, that it's okay to say "If you don't have Flash, my website won't work." Yet in the same regard, JavaScript is expected to degrade peacefully if the user does not have it enabled.

I personally favor the "HTML5" approach, in opposition to Flash, due to the poor performance Flash brings to Mac OS X and Linux

The overall outlook of the Flash way vs. the JavaScript way seems like the biggest challenge to me in Steve Job's prediction of HTML5 overtaking Flash, and I personally haven't seen any sign of change.

Am I missing something?

HTML5 will probably not kill Flash. Although I'm an Actionscript 3 developer, I have little love for Adobe and if anyone is going to kill Flash, I believe it will be Adobe themselves by failing to adapt.

Web standards are great but inevitably changes take for ever.Solutions developed by smaller entities can implement changes and adapt faster. Look at how JQuery changed the perception of Javascript. Most people have already forgotten that until recently there was very little love for Javascript, which is probably where the degrade gracefully attitude comes from.

The consensus is now to complain about Flash , the real shame is what Adobe has done with it , or more to the point hasn't done to improve it. I agree with Steve Jobs on that one, Adobe are either lazy or misguided. In any case totally inefficient.

In my view there's nothing wrong with a plugin, provided it works as expected and with a penetration above 90% , Flash has/had the potential to become a standard itself... in another world that is.

You're talking about almost entirely different groups of people with very different worldviews. That's why they say two different things. Very few people are both gung-ho Flash fanatics and slavish adherents to progressive enhancement.

For the people who support Javascript, one of the big reasons many do so is that it's an open standard with free implementations that is accessible to anybody, not just those favored by Adobe. This feeling that Web content should be available to everybody on the Web also makes them hostile to Javascript that takes the same "My way or the highway" stance that led them to reject Flash.

It's not OK to say either of those, in the general case. However for some it's acceptable to give up on having a working site for some percentage of users.

It depends on the kind of project you are developing for.

It's only safe to assume the user will be able do interact only with the HTML (that's why it's a good idea to hijax your form instead of assuming the user will be able to run your ajax function)

As for FLASH I aways assume it will be unavailable to a small be considerable group of users (iphone, and ipad user won't be able to interact with your flash)

So basically, when developing a portal I assume that:

The user browser will be able to display HTML
There's a great probability that the user's browser will be able to interpret javascript
There's a considerably smaller probability that the user will have the flash plugin

My rule of thumb is: If you have to have flash at all use it for non-important stuff. All important stuff should be able to work fine with just HTML

The reason is because Flash has a penetration of around 99% of all internet connected computers, and acts exactly the same across the board. Flash has many features which are not replaceable (until very recently, thanks to HTML5 and better JavaScript implementations) While JavaScript implementations are all incomplete as well as varying in between browsers.

I'm not a flash developer, but I'm guessing there would be different methodologies too. The whole mantra of modern web development is a sort of additive synthesis, so you start with something basic, then work up from there, building up features as you go along.

The real reason is that if you use flash on your website, you probably don't give a toss about things like accessibility and other minor concerns.

JavaScript developers are also much nicer people.

Typically JavaScript is used to support basic but important operations, and being important goes hand in hand with high usage frequency, large audience, possibly business critical. Thus it is important that they require "peaceful degradation".

Flash tends to be used for splashy stuff, like games, heavy UI apps (like paint style programs). These tend to be less important and so less reason for them to degrade peacefully.

For example, I can see the Flash part of Google's analytics site making way for HTML5 in the future. It is suited to it. But something like Google's street view I see no real reason to go down the HTML5 route for it (although I suspect they still might).