rect.x.baseVal: 1
rect.x.animVal: 1
rect.y.baseVal: 2
rect.y.animVal: 2
rect.width.baseVal: 3
rect.width.animVal: 3
rect.height.baseVal: 4
rect.height.animVal: 4
Expected exception: NoModificationAllowedError: Cannot modify value of read-only SVGLength