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

200 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
200 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)
200 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)
200 months ago
How many people save bookmarks to their home screen?

Not just bookmarks. HTML5 web apps too.
Score: 1 Votes (Like | Disagree)
200 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
200 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

M5 MacBook Pro

RIP, MacBook Ultra

Monday October 19, 2026 9:37 am PDT by
Apple today sent out invites for an experience in Los Angeles on Wednesday, October 28, and the "Pro and tell" tagline on the invitation likely means that the rumored MacBook models with touch-enabled OLED displays will stick with MacBook Pro branding instead of the once-rumored "MacBook Ultra" name. The long-rumored "iPhone Ultra" ended up being named iPhone Duo, so speculation that Apple...
iPhone Duo Trio

Here's What Apple's Apps Look Like on the iPhone Duo

Tuesday October 20, 2026 11:12 am PDT by
With just three days to go until the iPhone Duo is released, Apple is getting ready for the launch. Behind the scenes, the App Store now has screenshots of Apple's built-in apps running on the Duo. We've seen some apps in marketing materials, but images of the ones we haven't seen give us an idea of what it will be like using the iPhone Duo day to day. Many apps are shown in landscape...
apple pro tell logo

Apple Announcing New Products Next Week: 'Pro and Tell'

Monday October 19, 2026 9:05 am PDT by
Apple's Greg Joswiak today hinted at new product announcements coming next week, sharing a social media post that says "Can't wait to pro and tell next week." Rumors suggest Apple is planning to debut the new MacBook Pro with an OLED touchscreen display, an M6 entry-level MacBook Pro, an M6 iMac, an iPad mini with an OLED display. Can't wait to pro and tell next week....
Latest Stories
Tesla App Gains iPad and iPhone Duo Support
Tesla App Gains iPad and iPhone Duo Support
3 hours ago
Apple Reportedly Boosts iPhone Duo Orders by 44%
Apple Reportedly Boosts iPhone Duo Orders by 44%
3 hours ago
Fortnite Returning to Australian App Store After Court Ruling
Fortnite Returning to Australian App Store After Court Ruling
4 hours ago
Apple Ordered to Open iPhone to Rival App Stores in Australia
Apple Ordered to Open iPhone to Rival App Stores in Australia
4 hours ago
Apple Suppliers Face Hurdles Cutting Circuit Board Emissions
Apple Suppliers Face Hurdles Cutting Circuit Board Emissions
5 hours ago
Things Updated for iPhone Duo With Adaptive Layout
Things Updated for iPhone Duo With Adaptive Layout
5 hours ago
Simplicity and Siri AI Are HomeView's Killer Features, Apple Says
Simplicity and Siri AI Are HomeView's Killer Features, Apple Says
5 hours ago
iPhone Duo Reviewers Really Miss Face ID
iPhone Duo Reviewers Really Miss Face ID
10 hours ago
Does the iPhone Duo Run Hot? Here's What Reviews Found
Does the iPhone Duo Run Hot? Here's What Reviews Found
12 hours ago
Apple Music's New Look is Now Live on Apple's Website
Apple Music's New Look is Now Live on Apple's Website
12 hours ago
Anthropic Launches Claude Duet, a Proactive AI Agent
Anthropic Launches Claude Duet, a Proactive AI Agent
13 hours ago
What 32,000 Folds Did to the iPhone Duo's Hinge
What 32,000 Folds Did to the iPhone Duo's Hinge
14 hours ago
iPhone Duo's Hidden FaceTime Camera Takes 'Trash' Photos
iPhone Duo's Hidden FaceTime Camera Takes 'Trash' Photos
15 hours ago
iPhone Duo Has 'Edge Light' Feature That Debuted on Macs Last Year
iPhone Duo Has 'Edge Light' Feature That Debuted on Macs Last Year
16 hours ago
Apple Support App Updated for iPhone Duo's Larger Display
Apple Support App Updated for iPhone Duo's Larger Display
16 hours ago
Amazon Sweetens the Deal on Entry-Level 16-Inch MacBook Pro With $570 Off
Amazon Sweetens the Deal on Entry-Level 16-Inch MacBook Pro With $570 Off
16 hours ago
iPhone Duo Tips Over on MagSafe Stands When Unfolded
iPhone Duo Tips Over on MagSafe Stands When Unfolded
16 hours ago
Apple Music's New Look Officially Announced
Apple Music's New Look Officially Announced
18 hours ago
iPhone Duo Supports Apple Pencil Starting With iOS 27.2
iPhone Duo Supports Apple Pencil Starting With iOS 27.2
18 hours ago
iPhone Duo Accessories Roundup: Cases and Screen Protectors From OtterBox, ZAGG, and More
iPhone Duo Accessories Roundup: Cases and Screen Protectors From OtterBox, ZAGG, and More
19 hours ago
Apple Stores Will Have 'Limited' Availability of iPhone Duo for Walk-In Customers
Apple Stores Will Have 'Limited' Availability of iPhone Duo for Walk-In Customers
20 hours ago
iPhone Duo Reviews Explain Why Device is Both 'Fun' and 'Frustrating'
iPhone Duo Reviews Explain Why Device is Both 'Fun' and 'Frustrating'
20 hours ago
Apple Says 'Reachability' Feature Coming to iPhone Duo Later This Year
Apple Says 'Reachability' Feature Coming to iPhone Duo Later This Year
21 hours ago
Loop Capital Cuts Apple Rating Over iPhone Sales Outlook
Loop Capital Cuts Apple Rating Over iPhone Sales Outlook
1 day ago
Apple Stores in Bordeaux and Lille Looted During French Protests
Apple Stores in Bordeaux and Lille Looted During French Protests
1 day ago
Bluesound Adds Native Apple Music Support
Bluesound Adds Native Apple Music Support
1 day ago
Apple CEO John Ternus Explains What Makes Good Product Design
Apple CEO John Ternus Explains What Makes Good Product Design
1 day ago
UK Proposes New Ways to Help Apple Pay Rivals
UK Proposes New Ways to Help Apple Pay Rivals
1 day ago
WhatsApp Developing In-App Browser for All Chat Links on iPhone
WhatsApp Developing In-App Browser for All Chat Links on iPhone
1 day ago
Apple's App Store Chief Explains Its Push for Premium Games
Apple's App Store Chief Explains Its Push for Premium Games
1 day ago