Off Topic: iOS 7 Safari is the buggiest version since version 1
Bad news: iOS 7's HTML5 is full of bugs
'This is the buggiest Safari version since 1.0,' says one HTML5 development expert
Bad news: iOS 7's HTML5 is full of bugs
By InfoWorld Tech Watch
Created 2013-09-27 03:00AM
Apple's iOS 7  is plagued with HTML5 defects related to the Web SQL database, home-screen widgets, gestures, and animations. Maximiliano Firtman, an HTML5 developer and author of several popular Web programming books, revealed several of these bugs in his blog . And Michael Mullany, CEO of Web development environment vendor Sencha, both confirmed Firtman's findings and found more problems  in Apple's HTML5 execution.
Firtman was even more direct: "I can say without fear of mistake that this is the buggiest Safari version since 1.0." He noted that some bugs were reported by developers in iOS 7's three-month beta period, but were not fixed in the released version.
One problem area Firtman described involves Web SQL permissions not working correctly when trying to expand the database size beyond 5MB. In previous versions of iOS 7, the limit was 50MB, so many apps will now exceed that limit in their database downloads. Worse, if that limit is exceeded, the user will get a confirmation dialog box to allow the larger download but then only the first 5MB will actually be downloaded.
Firtman noted a workaround: If the app requests 5MB or less the first time and then requests more data, the user gets the permissions dialog box, and iOS 7 allows the extra data. Also, the bug doesn't appear to occur when apps are running in full-screen mode, which is the default in iOS 7.
Another issue Firtman detailed relates to iOS's ability to save home-screen icons of Web pages so that users can access them quickly as if they were apps. Firtman said that any URIs in the Web address -- the portion after the domain name -- is ignored, so a home-screen Web app can't invoke any functions in the URI when opened. Likewise, cookies are now ignored when opening a home-screen app. Also, if you store more than four Web pages as home-screen apps, iOS 7 often replaces icons of existing home-screen apps with the newly saved ones -- you get that errant replacement once your device has four home-screen Web app icons on it.
Mullany noted that when managing application state in apps that use AppCache, the history object never updates, disabling history.back. This can cause applications to work incorrectly if they need a prior state to resume a function.
Another issue involves inconsistent rendering after rotating content, which Firtman noted in Safari and Mullany noted in other apps. Mullany also cited the following issues:
Launching and quitting the same home-screen app several times can hard-lock the device, requiring a hardware reboot.
On iPad, if the document body is set to 100 percent height, content is shifted upwards by 20 pixels in landscape mode. This can be worked around by calling window.scrollTo(0, 0) on the orientationchange event.
In certain cases, resizing a composited layer (an element with 3D transform) does not repaint it correctly. Instead, the cached bitmap is stretched.
Scripts running within Web Workers are not suspended unless either the originating page is explicitly killed, or the Safari process is explicitly terminated. The three techniques you'd expect -- switching to another tab, minimizing Safari, or turning off the screen -- don't stop Web Worker execution. "This is a serious issue that allows any Web page to drain the battery of an iOS 7 device and slow down performance of the whole system without a user alert," Mullany wrote. It may be related to iOS 7's new multitasking feature, which keeps app running when you switch to others rather than suspending them as before -- except for a small number of background services that Apple allows to keep running.
Firtman has many other complaints , although most are not bugs but frustrations due to the new look of iOS 7 as well as Safari's full-screen mode, which causes several common hacks not to work any longer.
This story, "Bad news: iOS 7's HTML5 is full of bugs ," was originally published at InfoWorld.com . Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog . For the latest developments in business technology news, follow InfoWorld.com on Twitter .
Application Development HTML5 Mobile Technology Apple HTML5 iOS Mobile Development Web Development
Source URL (retrieved on 2013-10-03 10:47AM): http://www.infoworld.com/t/html5/bad-news-ios-7s-html5-full-of-bugs-227685