canvas VS svg?

Answer 1

SVG, as Canvas, is a new feature of Html5...
Both are complementary, and handle their content very differently:

SVG handle vector graphics, as Canvas handle bitmaps.
SVG compose image with element accessible through DOM, while Canvas comes with a JS api for drawing on surface of element.
SVG can handle bitmaps, but isn't design for that puropose, and conversely, Canvas can handle vectors graphics, but isn't adapted too...

A third specialized container for drawing exist also with html5, designed for handle 3D through another specialized JS api: WebGL...