element.style is not supported as an lvalue in IE<9.
All the rest of the sane world that doesn't support IE<9 should be laughing
at me in pity right now.
* src/ui/styler/NaFieldStyler.js (hideField):
Use HTMLElement#setAttribute instead of HTMLElement#style as an lvalue
* test/ui/styler/NaFieldStylerTest.js: Modify test cases to check for
invocation of setAttribute
Field stylers now determine whether they've been applied to the target field
on their own, which solves the problem of the system getting out of sync.
* src/ui/styler/ErrorFieldStyler.js (isApplied): Added
* src/ui/styler/FieldStyler.js (isApplied): Added
* src/ui/styler/NaFieldStyler.js (isApplied): Added
* test/ui/styler/NaFieldStylerTest.js: Test for #isApplied
This is necessarily primarily for a specific case: option elements in IE,
which cannot be styled. >:O
This implementation is not complete: we want to re-attach the field at the
same position it was at before it was detached. This might not be
trivial---imagine if its sibling was also detached.
* src/ui/styler/NaFieldStyler.js (isSubField): Receive field instead of
element (to check parent)
(applyStyle, revokeStyle): Detach and re-attach field from/to DOM
respectively
* test/ui/styler/NaFieldStylerTest.js: Associated tests