iOS 4.3 Web performance differences a security matter

By Marco Tabini, Macworld |  Security, Apple, iOS 4.3

One of the lesser-known improvements in the iOS 4.3 update is a significant boost in the speed of Safari's JavaScript performance, thanks to the incorporation of the Nitro engine used in the Mac OS X version of Apple's Web browser. However, a number of recent stories have claimed that the performance of Web apps and apps that embed a Web browser in iOS 4.3 is significantly worse than that of Apple's own Mobile Safari Web browser.

Conspiracy theorists are out in force, saying that this is nothing more than a subtle ploy by Apple to make Web apps appear slower than their native counterparts, in an effort to keep developers tight in the evil grips of the App Store.

Apple has acknowledged the discrepancy, telling The Register, "The embedded web viewer does not take advantage of Safari's web performance optimizations," although the company has called some of the performance benchmarks "flawed". But it is a squeeze play from Apple? Nobody can say for sure, but just as John Gruber pointed out on his Website, Daring Fireball, on Thursday, there are some valid technical reasons behind what is happening, which shed some fascinating light on how iOS works and the lengths to whichApple has gone to keep things safe and secure on the company's mobile operation system.

How JavaScript works

At the core of the issue is a technology called Nitro. Initially dubbed Squirrelfish Extreme and announced in 2008, Nitro is the underlying engine that makes it possible for Web pages to run JavaScript code. This, in turn, is one of the ways in which a Web page can provide complex interactive features such as animations or application-like functionality.

JavaScript is an interpreted language, meaning that every time a Web page containing JavaScript code is loaded, the browser must evaluate the code and translate it into a series of actions that the computer can execute. In human terms, this would be analogous to having to re-take all your driver's ed lessons every time you want to take the car for a ride because you forget how to drive the moment you step away from the steering wheel.

Originally published on Macworld |  Click here to read the original story.
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