SVG re-ordering z-index (Raphael optional)

Question

How can I reorder Raphael or their underlying SVG elements after creation. Better yet, do something like layers exist in SVG?

Ideally I would like two or more layers

Answer 1

If you're using Raphael, popping elements backwards and forwards is very straightforward:

element.toBack()
element.toFront()

Here's the relevant documentation.