What's new for web developers in iOS 5 Safari?

Question

From the Apple WWDC we have learned that iOS Safari 5 has tabs, and the new Reader and Reading List functionality.

None of which is particularly informative for web developers. What are the new features relative to CSS (position fixed?), Javascript (web workers?) and DOM (gesture events?)?

Answer 1

• It appears we do indeed get position:fixed and also overflow:scroll, see http://functionsource.com/post/ios5-positionfixed-overlayscroll
• And also Web Workers, and various input tag enhancements. JS Speed enhancements as well: More comprehensive details here: http://davidbcalhoun.com/2011/new-mobile-safari-stuff-in-ios5-position-fixed-overflow-scroll-new-input-type-support-web-workers-ecmascript-5
• Cubiq aka Matteo Spinelli, creater of iScroll chimes in: http://cubiq.org/what-you-can-really-do-with-native-position-fixed
• "iOS 5 supports contenteditable! Even tinyMCE works." http://twitter.com/#!/rakaz/status/78716905648685056:
• "Safari on iOS 5, HTML5 evolution for iPhone and iPad" by Maximiliano Firtman: http://www.mobilexweb.com/blog/ios-5-iphone-and-ipad-html5
• "iOS 5 supports contenteditable, and tinyMCE works, per @rakaz @austegard What's new for web developers in iOS 5 Safari?" from https://twitter.com/#!/puresight/status/92825096477093888
• Video demonstration of TinyMCE on iPad running beta 6: http://www.midwesternmac.com/blogs/jeff-geerling/wysiwyg-editing
• "iOS 5 and New Features for Web Developers": http://samuli.hakoniemi.net/ios-5-and-new-features-for-web-developers/
• From personal, empirical experience: An iframe in iOS5 will expand so that its entire content is visible, no matter the width and height constraint given to it by the parent document. (This looks like a lazy approach to fixing the iOS4 two-fingers-needed-to-scroll-iframe-content problem.)