[yjftsjthsd-h]

Devil's advocate: Having only 1 engine means that a website only needs to test once to make sure they support all iPhone+iPad browsers.

[modeless]

You might think so but you would be wrong. For example, try making a link to add a calendar event from Safari vs. Chrome vs. Facebook in-app browser, etc.

[hashhar]

Write to the spec and forget about it.