Two different width and height attributes

Question

Why do we have width & height attributes for Svg and also a different eight & height attribute for <rect> ?

Answer 1

<svg> is the root of all your svg shape elements, then height and width define the svg canvas size. Futhermore every svg shape can use own width and height attribute which values can be valutated in different ways. At example, if <svg> root element define an attribute viewBox like viewBox="0 0 30 30" (indicate a virtual coordinate system space where 0 0 is at top left of svg, 30 30 mean width height of this coordinate system space), all shape height/width will not represent in pixels but proportion (width="15" set a shape like half root width)