4 ms·
> Web browsing: Certain complex web technologies, like just-in-time (JIT) JavaScript compilation, are disabled unless the user excludes a trusted site from Lock
by brundolf 4y ago
> Web browsing: Certain complex web technologies, like just-in-time (JIT) JavaScript compilation, are disabled unless the user excludes a trusted site from Lockdown Mode.
That's very cool actually. You can keep JS enabled but choose to make it run more slowly in exchange for better sandboxing
- kylehotchkiss 4y agoI originally understood this to mean JS was disabled entirely in safari when enabled unless a site is allowlisted. Does this mean the web will run JS “normally” but slower? Does the speed of modern phones mean a slower style of JS processing might be less discernible?
- brundolf 4y agoThat's my interpretation. Modern JS engines have multiple tiers of optimization, which they apply in different ways based on how "hot" a piece of JavaScript is. JIT is the highest level of optimization, but also means generating and executing native code on the fly, which I assume leaves the door open for worse exploits if there's a bug in the engine. This is in contrast with bytecode interpretation, which is slower but available.