Re: [css-syntax] Error-correcting unclosed empty url()

On Oct 8, 2014 12:46 AM, "Simon Pieters" <simonp@opera.com> wrote:
>
> On Tue, 07 Oct 2014 23:47:11 +0200, Tab Atkins Jr. <jackalmage@gmail.com>
wrote:
>
>> Right now, the Syntax spec defines url() to be handled the same way as
>> anything else when you hit of EOF while it's unclosed - it gets closed
>> and is valid.
>>
>> That is, the following two examples are equivalent per spec, assuming
>> the file ends after the last character:
>>
>>     foo { background-image: url(foo
>>
>>     foo { background-image: url(foo)}
>>
>> This behavior is inconsistent across browsers - Firefox agrees with
>> the spec and treats these as equivalent, but Chrome refuses to
>> recognize a url() as valid until it sees the close parenthesis.
>>
>>
>> Browsers currently agree in behavior when the url() is completely empty,
like:
>>
>>     foo { background-image: url(
>>
>> They all treat this as invalid and throw out the declaration.
>
>
> Gecko treats it as url("").
> IE11 treats it as none.
> Other browsers throw out the declaration.
>
> http://software.hixie.ch/utilities/js/live-dom-viewer/saved/3244
>
>
>> But
>> they all consider this valid:
>>
>>     foo { background-image: url()
>>
>> So the error-handling is inconsistent with how other functions work.
>>
>>
>> How should we proceed?  I suggest keeping the current spec behavior.
>> When there's some content in the url(), this matches at least one
>> browser.  When it's empty, it matches no browser I've tested, but it's
>> consistent with the rest of the platform, and I doubt content is
>> relying on this behavior.
>
>
> Yeah, I agree the syntax spec is OK as is.
>
> IE's behavior for url( is the same as what it does for url(""). HTML
generally also has this behavior for resources that are embedded, like <img
src=""> doesn't fetch anything (but <a href=""> is allowed).
>
> Maybe we should make CSS special-case the empty string URL, like IE and
HTML?

That's sensible behavior, and matching HTML and IE is a big plus. I'll
propose this tomorrow.

~TJ