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RE: SVGT 1.2: "evt" vs "event" as the implicit event argument to event handlers

From: Doug Schepers <doug.schepers@vectoreal.com>
Date: Thu, 20 Apr 2006 11:35:31 -0400
To: "'Maciej Stachowiak'" <mjs@apple.com>, <www-svg@w3c.org>
Message-Id: <20060420153531.EE02D19665B@plunder.dreamhost.com>

Hi, Maciej-

Thanks for your suggestion. We talked it over, did some research, and
discussed the ramifications of your suggestion. Our reply is below.

Maciej Stachowiak wrote:
| SVG Tiny 1.2 calls for handler element bodies to implicitly create a  
| function with a paramater named "evt" for the event. SVG Full 
| 1.1 did  
| the same for event handler attributes. However, the longstanding  
| universal practice of (X)HTML UAs is to name this parameter "event".  
| It seems like it will be terribly confusing in a CDF enviornment for  
| SVG event handlers to name this parameter "evt" and for other  
| languages to use "event", especially since many major browsers are  
| now implementing HTML+SVG. There does not seem to be any 
| advantage to "evt".
| I recommend renaming this parameter from "evt" to "event". 
| This would  
| break compatibility with SVG 1.1 but the alternative is ongoing  
| confusion for content authors. Another option is to require both  
| "evt" and "event" parameters but deprecate "evt".

SVG references DOM2 for the event listener functionality, including the
names of the parameters. DOM2 does not mention the parameter 'event', but
does explicitly define 'evt' (of type Event) [1]. DOM2, DOM3, SVG, and
VoiceXML all use 'evt', and other specs implicitly use it by referring to
DOM2, so we feel like we that there is an established precedent within W3C
specs to use 'evt'. Also, there is a lot of existing SVG content that uses
'evt', so it's not just a matter of breaking compatibility with the SVG 1.1

We could not find the parameter 'event' defined in any XML or XHTML spec,
but we recognize that it is widely implemented in HTML UAs. We suggest that
a good way forward is to require both 'event' and 'evt', as you suggest, but
to deprecate 'event' instead. However, this is outside the scope of the SVG
WG, but may be appropriate for WebAPI, and should be addressed in CDF, as

If this does not satisfy your suggestion, please let us know within 2 weeks.


Doug, on behalf of the SVG WG
Received on Thursday, 20 April 2006 15:35:41 UTC

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