This would probably be a better place to ask:
https://devforums.apple.com/community/safari/iphonewebappsYou need to be a registered Apple developer to access that forum, but the Safari developer program is free, so it's just a matter of registration.
As well, there is extensive documentation available here:
https://developer.apple.com/devcenter/safari/index.actionI'm pretty sure, though, that the answer is "no". This isn't exposed through the browser. It's an Objective-C Framework that is accessible to iOS apps.