But now the web is plagued by javascript doing the same, often even more intensively. Is it better or worse?
Flash had a much more arms-length relationship to the browser and wasn't able to be used as a surveillance tool as effectively as Javascript can be.
The constrained nature of Flash made it less of a threat to an open and standards-based web than Javascript (and more broadly WASM).
Edit: On the last point - Flash wasn't able to boot a virtual x86 in a browser. Obligatory reference: https://www.destroyallsoftware.com/talks/the-birth-and-death...
Thanks to the ADA, American sites (or sites that do a lot of business with America) must work with assistive technologies, mainly web browsers designed for the blind. Most of those do not run js. So, you cannot design your website so that it doesn't work with js disabled, unless you are willing to expose yourself to massive legal liability. People used to ignore this a lot, but since Domino’s Pizza v. Guillermo Robles, most sites have been fixed so that they are usable without js.
I strongly recommend getting ublock, blocking all js by default, and then whitelisting sites where it is required/useful. It's hard to overstate just how much better it makes browsing in general.
My non-technical friends and family can't do that. Trying to impose that upon them would just frustrate them (and, for my family, increase tech support calls to me).
All my banking and insurance sites are useless w/o Javascript. Squarespace sites, Twitter, Imgur, don't work worth a damn without Javascript. I just gave up and mostly gave Google properties a pass to get Youtube to work. (I don't use Gmail so I have no idea how bad it would be.)
A site better be pretty damned compelling before it rises to the level of getting opened in an unconstrained browser setting. I just end up not opening a lot of stuff (or just closing it again when it lights-up "NoScript").
https://chrome.google.com/webstore/detail/js-toggle/bnhjfamo...
In the more general sense, a strictly online service that has no alternate means of access probably does have at least some responsibility under the ADA.
In particular, Robles wanted the court to order Domino's to make their site WCAG-2.0 compliant. WCAG is completely silent on JavaScript. It's possible that some screen readers don't support JavaScript, but if Domino's site used ARIA tags and complied with WCAG the court would almost certainly consider that accessible (there's no official DoJ guidelines on what constitutes accessibility, so the court and businesses have latitude here.)
The ADA is all about reasonable accomodations. Supporting major screen readers is reasonable; supporting all of them clearly isn't. 98% of screen reader users have JS enabled (https://webaim.org/projects/screenreadersurvey4/#javascript), so it's clearly reasonable to provide an accessible webapp.
Flash cookies, anyone?
These were the only mainstream way to keep tabs on you across different browsers.
Flash is an intrinsically more efficient format; it was designed back when 56k modems were the norm, and computers far less powerful, so SWF made use of lots of interesting tricks to squeeze the most of out the platform and be extremely simple to parse.
Those who remember playing Flash games will definitely know just how much computing power they needed --- a fraction of that needed for today's "equivalent" with HTML/CSS/JS.
You will never get close to that level of efficiency with HTML/JS/CSS, although they are certainly trying with things like WASM.
I say this as someone who has implemented a significant part of a SWF player, including parts of the AS2 VM.
JavaScript has holes basically every month too
Well it still may be harder to attack this than Flash, but still...
The only people who could improve the Flash plugin's performance were the people at Adobe working on it. And, well, Adobe just doesn't give two shits about performance of any of their tools unless they absolutely have to.
Adobe approached Apple many times to nail down performance issues and Apple blew them off
The argument has merit that Apple wanted a more precise control over user experience, and badly written Flash apps could disrupt that, but I honestly believe that was a secondary concern compared to protecting their App Store revenue stream.
Edit: I was 9 when Jobs wrote his thing on Flash, so I appreciate the downvotes for asking a question?
Besides, there's a lot more to SWF than the scripts.
https://www.adobe.com/content/dam/acom/en/devnet/pdf/swf-fil...
Straight from the horse's mouth, as they say.
There's also a few other implementations, although they found use embedded in games and such instead of being browser plugins.