We never say that it isn't. There is a reason Google developed NaCl in the first place that inspired WebAssembly to become the ultimate sandbox standard. Not only that, DOM, JS and CSS also serves as a sandbox of rendering standard, and the capability based design is also seen throughout many browsers even starting with the Netscape Navigator.

Locking down features to have a unified experience is what a browser should do, after all, no matter the performance. Of course there are various vendors who tried to break this by introducing platform specific stuff, but that's also why IE, and later Edge (non-chrome) died a horrible death

There are external sandbox escapes such as Adobe Flash, ActiveX, Java Applet and Silverlight though, but those external escapes are often another sandbox of its own, despite all of them being a horrible one...

But with the stabilization of asm.js and later WebAssembly, all of them is gone with the wind.

Sidenote: Flash's scripting language, ActionScript is also directly responsible for the generational design of Java-ahem-ECMAScript later on, also TypeScript too.

> Sidenote: Flash's scripting language, ActionScript is also directly responsible for the generational design of Java-ahem-ECMAScript later on, also TypeScript too.

I feel like I am the only one who absolutely loved ActionScript, especially AS3. I wrote a video aggregator (chime.tv[1]) back in the day using AS3 and it was such a fun experience.

1. https://techcrunch.com/2007/06/12/chimetv-a-prettier-way-to-...

How did you got that impression?

There is the universal hate for flash because it was used for ads and had shitty security, but anyone I know who actually used AS3 loved it.

At its peak, with flex builder, we also had a full blown UI Editor, where you could just add your own custom elements designed directly with flash ... and then it was all killed because Apple did not dare to open source it, or put serious efforts on their own into improving the technical base of the flash player (that had aquired lots of technical dept).

> There is the universal hate for flash because it was used for ads and had shitty security

That's only one side of it. Flash was the precursor to the indie/mobile gamedev industry we have today (Newgrounds, Miniclip, Armor Games), before smartphones become ubiquitous. Not to mention some rather creative websites, albeit at the cost of accessibility .

Flash's only fault was it's creators were gobbled up by Adobe, who left it in the shitter and ignored the complaints people had about it's security issues.