do not copy form values if value attribute is set

[abradley2]

*Updated based on some discussion in this issue

Because an input that looks like this <input type='text'/> will still have a value of "", the el.value method can't be used to distinguish between how it should update different than something like <input type='text' value="" />

Use case:

Between updates: <input type='text' /> = will copy over the value, because hasAttribute('value') will return false even after user input

<input type='text' value=${val} /> will set the value to whatever val is, even if it is an empty string, because hasAttribute('value') will return true

This relates to the issue here: https://github.com/maxogden/yo-yo/issues/66

[toddself]

This sounds like a valid fix. Are we sure hasAttribute works the same way in older browsers? Speaking of, @maxogden is there a cut-off for browser support for this library?

[yoshuawuyts]

@toddself iirc so far for choo we've been targeting IE10+ because anything below that is like 1% market share - which is less than mobile Opera and most people don't really account for that - can't speak for yo-yo ofcourse, but I would assume it'd follow something pragmatic (:

[Mr0grog]

FWIW, hasAttributeNS() is supported in IE as far back as 9. In IE8, you’d have to fall back to either hasAttribute() or the attributes property.

[Mr0grog]

Errr, sorry, I had misread/miscarried some conversation from #66 over here; I see this isn’t using hasAttributeNS(). Anyway, hasAttribute() works at least as far back as IE8. I don’t have an older IE to test.

[harrygr]

This looks like a needed fix - any chance this could get merged?

[kristoferjoseph]

@yoshuawuyts @maxogden @shama Can we merge this pretty please? Thank you kindly.

[yoshuawuyts]

v1.4.1