Automatically check input validity before saving values

[tdulcet]

This library should automatically call either the reportValidity() or checkValidity() functions before saving input, without having to manually register a save trigger for each option group to do so. See here and here for more info.

Note that this is also supported by a similar library: https://github.com/fregante/webext-options-sync.

[rugk]

Oh, indeed, this sounds very nice!
It eases validation and is purely HTML5, I like that. 😃