[whatwg] <marquee> feedback

Ian Hickson ian at hixie.ch
Thu Apr 28 12:17:45 PDT 2011

On Tue, 7 Dec 2010, Andy Estes wrote:
> I recently implemented HTML5's IDL definition for <marquee> in WebKit 
> (https://webkit.org/b/49786) and noticed a few differences between how 
> HTML5 specs marquee and how IE implements it. I noticed the following 
> two discrepancies:
> 1) For scrollAmount, scrollDelay and loop, IE does not allow the content 
> attribute value to contain trailing non-numeric characters, although 
> such characters are allowed according to HTML5's "rules for parsing 
> non-negative integers" (section IE will return the default 
> value for these attributes if non-numeric characters are encountered, 
> but HTML5 says to parse up to the first non-number and return that 
> value.
> 2) For scrollAmount, scrollDelay and loop, if a value is specified that 
> exceeds 2^31-1, IE will return 2^31-1. HTML5 says that for reflected 
> unsigned longs, if a value is larger than 2^31-1, the default value, or 
> 0, should be returned (section 2.8.1).
> Perhaps these differences aren't specific to <marquee> but rather true 
> for all unsigned content attributes in IE. In any event, I wanted to 
> point out the differences in these edge cases and ask if they are 
> intentional or not. I'd be happy to file a bug if that's the correct 
> thing to do.

On Tue, 7 Dec 2010, Jonas Sicking wrote:
> Unless this breaks websites, it seems like a good thing to have 
> consistent parsing across multiple attributes. Both for implementors and 
> authors.

This is an area where there is a surprisingly low level of 
interoperability amongst the browsers near edge cases. The current spec 
text is the result of careful examination of a number of attributes, and 
is an attempt to try to be as consistent across attributes as possible.

So I haven't changed marquee for this.

If there are compat issues with existing sites, please do reraise this, as 
this would change the equation significantly.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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