iOS 5 to Bring Nitro JavaScript Speed Enhancements to Home Screen Web Apps - MacRumors
Skip to Content

iOS 5 to Bring Nitro JavaScript Speed Enhancements to Home Screen Web Apps

by

ios5 iconBack in March, we noted that Safari speed improvements in iOS 4.3 brought about by the addition of a new Nitro JavaScript engine did not extend to web apps launched from the home screen, meaning that webpages launched from convenient home screen icons exhibit significantly slower performance than those exact same pages loaded manually or from bookmarks within Safari.

As noticed by CNET, a thread on Hacker News shares that iOS 5 does in fact provide home screen web apps with access to the Nitro capabilities, making them comparable to their directly-loaded counterparts.

Q: Did they fix the bug from 4.3 where home screen web apps don't use Nitro?

A: This is probably breaking my NDA to say this, but yes, they did. Web.app now has the "dynamic-codesigning" entitlement, which enables Nitro.

The thread goes on to reveal that the Nitro implementation does not extend to web pages loaded within other apps that take advantage of UIWebView to provide browser functionality without redirecting users out of the app and into Safari directly. That omission is reportedly due to restrictions that prevent the Nitro entitlement from being extended to all apps for security reasons.

Top Rated Comments

198 months ago
How many people save bookmarks to their home screen?

Macrumors has been on my home screen since I got the iPhone
Score: 8 Votes (Like | Disagree)
nagromme Avatar
198 months ago
So all the absurd paranoia about how Apple is trying to slowly and sneakily “kill” web apps can evaporate now? :o
Score: 5 Votes (Like | Disagree)
198 months ago
Uh, how would this break NDA? I presume it's in the developer copy everyone has access to? Does the guy answering this have some credentials we don't know about?

The developer copy is theoretically for developers only... Hence the name. And therefore its covered by the NDA. It's so we don't all reveal the secret feature you're not meant to know about yet. You know the one...
Score: 3 Votes (Like | Disagree)
198 months ago
How many people save bookmarks to their home screen?

Not just bookmarks. HTML5 web apps too.
Score: 1 Votes (Like | Disagree)
198 months ago
I'm really glad that this FIX isn't getting a ton of fanfare.
We shouldn't be patting Apple on it's head and cheering them for fixing their own engineering mistakes.

How many people save bookmarks to their home screen?
m.youtube.com > Apple's native app. BY FAR


Macrumors has been on my home screen since I got the iPhone
To be fair, this means nothing since no one knows when you got your iphone.
It could have been five minutes before posting that post.
:-/
Score: 0 Votes (Like | Disagree)
chrmjenkins Avatar
198 months ago
The developer copy is theoretically for developers only... Hence the name. And therefore its covered by the NDA. It's so we don't all reveal the secret feature you're not meant to know about yet. You know the one...

And by developer you mean any joe blow willing to drop 100 bucks to download iOS 5 early. There's no way Apple would try and hunt down every last person who dropped the 100 and is leaking stuff that is basically public knowledge from using the developer build.
Score: 0 Votes (Like | Disagree)

Popular Stories

Four iPhone 18 Pro Colors Mock Feature

iPhone 18 Pro: Pre-Orders and Release Date

Sunday August 16, 2026 8:24 pm PDT by
Apple has yet to reveal when the iPhone 18 Pro and iPhone Ultra will be announced and released, but the dates usually follow a familiar pattern. As usual, the event is expected to take place in the first half of September. Labor Day falls on September 7 this year. The last time the holiday was on that day was in 2020, but the iPhone event that year was delayed until October due to the...
apple camera airpods

Apple's Camera-Equipped AirPods Confirmed: See Them in Action

Monday August 17, 2026 6:21 pm PDT by
Apple is working on camera-equipped AirPods that appear to be nearly ready to launch, based on a video MacRumors found in the macOS Tahoe 26.7 release candidate. In a short demo, a man holds a book up so the camera in the AirPods can see the title. "With Visual Intelligence, your world becomes savable. See something you like? Just ask me to save it for later," says the voiceover text. Here ...
iPhone 18 Pro Dark Cherry Feature

iPhone 18 Pro and iPhone Ultra: New Details Leak as Apple Event Nears

Monday August 17, 2026 11:09 am PDT by
"iPhone Ultra" supply will be very limited when the foldable device is first released later this year, according to Fixed Focus Digital, a known leaker on the Chinese social media platform Weibo. The account also claimed that the iPhone 18 Pro's A20 Pro chip will be up to 18% faster and up to 30% more power efficient compared to the iPhone 17 Pro's A19 Pro chip. The A20 Pro chip will be the...