does <set> add an attribute to node.attributes

In this funny little example:
http://srufaculty.sru.edu/david.dailey/svg/test/changeAttr4a.svg

I measure the number of attributes associated with a node before and after applying a 
<set attributeName="stroke-dasharray" begin="mouseout" to="0" onbegin="aftercount()"/>

to an object that previously had no stroke-dasharray. 

Opera says the thing has 10 attributes before and 11 after. Firefox and ASV+IE tell me that it has 10 both before and after. Chrome and Safari seem a bit displeased with the experiment in general (handling the rollover effect in a way that makes me displeased and not enjoying my attempt to trigger script from set.begin  -- frankly I wasn't at all sure that that would work at all anyhow and was rather pleased to see that it did, so it may not be webkit's problem!)

Anyhow, I went looking in the SVG 1.1 spec to see if I could see relevant language, but didn't see the answer in any obvious place.

ideas?
David