Last weekend, I landed a couple of fixes to improve the integration of SVG with existing Gecko functionality. (To be exact, Takeshi Kurosawa and I fixed bug 329212 and bug 374216) These improvements are both available in nightly builds.
In particular, we now support setting SVG element.style.property values e.g. element.style.fill=”green”. This feature was sufficiently popular that Google’s SVG Web project took the time to patch Firefox to implement this whenever it was loaded. It’s possible that this change may cause some pages written to target Microsoft Explorer filter implementation to display strangely since a test like if (element.style.filter) will now pass in both IE and Gecko. If you have such tests you may need to update them to ensure that they really do only catch IE.
We also display tooltips in SVG now by converting <title> elements into tooltip text so you won’t need to roll your own tooltips in future.