Why does iOS 4.3 run home screen web apps two times slower?

iOS is throttling web apps that are saved and executed from home screen, according to an exclusive report by The Register. The publication found out that such home screen web apps run “roughly two to two and a half times slower” as opposed to executing them directly from the Safari browser. The issue was discovered in the recently released iOS 4.3 software which updated Safari with a speedy JavaScript engine dubbed Nitro.

The publication notes that the Nitro engine fails to kick in for home screen web apps while offline caching, asynchronous mode of execution and other HTML5 goodies are also off limits. Is Apple attempting to derail iOS web development in order to push native App Store programs? Hard to tell. When the original iPhone came out, Apple suggested that developers use common web technologies. When the first official SDK was unleashed months later, web apps quickly took a backseat on iOS devices. On the other hand, Safari Dev Center encourages web-based iOS development and Steve Jobs stressed numerous times Apple’s support for two platforms, HTML5/CSS and the curated App Store platform.

And if Apple wanted to cripple web apps, wouldn’t they also want to throttle them directly in Safari, not just from the home screen? Of course, Apple has a vested interest in native apps due to a 30 percent cut they take from sales. I’ve argued nearly two years ago that the web is the ultimate app store and it’s true that many native apps are easily replicated with HTML/CSS, especially the stuff like news readers, social networking clients and more. Also important, web apps run on any device with a standards-complaint browser whereas their native counterparts lock you into a specific mobile platform.

On the other hand, consistent user experience has always been Apple’s top priority and web apps take away that control from them by mimicking native iOS look-and-feel via hard-coded style sheets. This is in stark contrast to native apps that go through APIs which take care of rendering the most up-to-date user interface elements.