Firefox has supported all SVG 1.1 filter primitives since Firefox 3, however until now it has only supported SourceGraphic and SourceAlpha pseudo inputs. Fortunately these are by far the most common.
Firefox 17 includes support for an additional two pseudo inputs – FillPaint and StrokePaint. The SVG testsuite has an example showing how they can be used.
Even though HTML doesn’t use the SVG fill and stroke CSS properties, you can still set them in Firefox to have StrokePaint and FillPaint filters with HTML.