Apple has introduced iOS 4.3, the latest version of its mobile operating system. New features include: faster Safari mobile browsing performance with the Nitro JavaScript engine; iTunes Home Sharing; enhancements to AirPlay; the choice of using the iPad side switch to either lock the screen rotation or mute the audio; and the Personal Hotspot feature for sharing an iPhone 4 cellular data connection over Wi-Fi.

“With more than 160 million iOS devices worldwide, including over 100 million iPhones, the growth of the iOS platform has been unprecedented,” said Apple CEO Steve Jobs at a special media event today. “iOS 4.3 adds even more features to the world’s most advanced mobile operating system, across three blockbuster devices — iPad, iPhone and iPod touch — providing an ecosystem that offers customers an incredibly rich experience and developers unlimited opportunities.”

He said the Safari mobile browsing experience gets even better with iOS 4.3. The Nitro JavaScript engine that Apple pioneered on the desktop is now built into WebKit, the technology at the heart of Safari, and more than doubles the performance of JavaScript execution using just-in-time compilation. With the Nitro JavaScript engine, Safari purportedly provides an even better mobile browser experience working faster to support the interactivity of complex sites you visit on a daily basis.

New iTunes Home Sharing allows iOS 4.3 users to play music, movies and TV shows on an iPad, iPhone or iPod touch from their iTunes library on a Mac or PC over a local Wi-Fi network. With a tap you can enjoy all the media in your iTunes library wherever you are in your home. You can stream a movie from your Mac in one room to your iPad in another or stream an iTunes mix to your iPod touch from the office to the kitchen.

iOS 4.3 includes enhancements to AirPlay, the wireless technology that allows users to stream music, photos and video to Apple TV. With iOS 4.3 you can stream additional content including video from third party apps and websites, videos from the Photos app and previews from the iTunes app to your TV. AirPlay also allows you to bring photos to life on the TV screen by using one of the new slideshow transitions, or shoot a video on your iPad 2, iPhone or iPod touch and stream it directly from the Photos app to Apple TV.

The new Personal Hotspot feature in iOS 4.3 lets you bring Wi-Fi with you anywhere you go, by allowing you to share an iPhone 4 cellular data connection with up to five devices in a combination of up to three Wi-Fi, three Bluetooth and one USB device. Once the feature is enabled, a status bar displays how many devices are currently connected. Every connection is password protected and when not in use Personal Hotspot turns itself off to save battery life.

iOS 4.3 will be available to iPad, iPhone and iPod touch users as a free software update on Friday, March 11. iOS 4.3 is compatible with iPad, iPad 2, iPhone 3GS, iPhone 4 (GSM model), plus third and fourth generation iPod touch.