iOS 5 could fix some slow Web apps

A Hacker News comment indicates that Web apps launched from iOS home screen will get the same Nitro speed boost that apps launched from within Safari already got.

Safari on iOS comes with an option to make an icon on the home screen for easy access later to Web sites or Web apps, but using that icon would deprive users of a JavaScript speed boost.
screenshot by Stephen Shankland/CNET

It looks likely that Apple's iOS 5 will will address an issue that deprived some Web apps from a speed boost that came to the mobile version of Safari.

On iOS, Web sites and Web apps can be launched from an icon that the user places on the home screen from Safari. Those apps didn't benefit from a speed-up that came with Safari in iOS 4.3, though: the Nitro engine that runs Web-based code is written in the ever-more-important JavaScript language.

It appears iOS 5 could address this issue, though.

"Did they fix the bug from 4.3 where home screen Web apps don't use Nitro?" asked user MatthewPhillips on Hacker News yesterday. The reply from Xuzz: "This is probably breaking my NDA to say this, but yes, they did. now has the 'dynamic-codesigning' entitlement, which enables Nitro."

There's also a way to create Web apps on iOS that doesn't use Safari proper, an interface called UIWebView.

That doesn't look to be getting the Nitro speed-up for security reasons involving just-in-time (JIT) compilation that Nitro uses to create faster versions of JavaScript software on the fly.

"They don't [get Nitro benefits], but that's a security restriction," Xuzz said. "They can't give dynamic-codesigning to all apps, or their security (which that disables, as a requirement to enable the JIT) would then be useless."

Apple didn't immediately respond to a request for comment.