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 [border: (2px solid #FF0000)]
      RenderBlock {DIV} at (14,14) size 756x28
        RenderInline {B} at (0,0) size 25x28
          RenderText {TEXT} at (0,0) size 25x28
            text run at (0,0) width 25: "on"
        RenderInline {I} at (0,0) size 12x28
          RenderText {TEXT} at (25,0) size 12x28
            text run at (25,0) width 12: "o"
      RenderBlock {DIV} at (14,42) size 756x28
        RenderInline {B} at (0,0) size 54x28
          RenderText {TEXT} at (0,0) size 54x28
            text run at (0,0) width 54: "three"
        RenderInline {I} at (0,0) size 40x28
          RenderText {TEXT} at (54,0) size 40x28
            text run at (54,0) width 40: "four"
selection is CARET:
start:      position 2 of child 1 {TEXT} of child 1 {B} of child 1 {DIV} of root {BODY}
upstream:   position 2 of child 1 {TEXT} of child 1 {B} of child 1 {DIV} of root {BODY}
downstream: position 0 of child 1 {TEXT} of child 2 {I} of child 1 {DIV} of root {BODY}