layer at (0,0) size 800x600
  RenderCanvas at (0,0) size 800x600
layer at (0,0) size 800x600
  RenderBlock {HTML} at (0,0) size 800x600
    RenderBody {BODY} at (8,8) size 784x584
      RenderBlock {DIV} at (0,0) size 784x18
        RenderBR {BR} at (0,0) size 0x18
selection is CARET:
start:      position 0 of child 1 {BR} of root {DIV}
upstream:   position 0 of  of root {DIV}
downstream: position 0 of child 1 {BR} of root {DIV}