Input:
hello <b style="background-color:blue; color:white;">world</b> <a href="https://webkit.org/">WebKit</a>.<br>
<span style="background-color:yellow;">this is a <u><i>t</i>est</u> of <em>attributed</em> string.</span>

Output:
NSParagraphStyle:
Alignment 4
    LineSpacing: 0
    ParagraphSpacing: 0
    ParagraphSpacingBefore: 0
    HeadIndent: 0
    TailIndent: 0
    FirstLineHeadIndent: 0
    LineHeight: 0/0
    LineHeightMultiple: 0
    LineBreakMode: 0
    Tabs: ()
    DefaultTabInterval: 36
    Blocks: (
)
    Lists: (
)
    BaseWritingDirection: 0
    HyphenationFactor: 0
    TighteningForTruncation: YES
    HeaderLevel: 0
[hello ]
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[world]
    NSBackgroundColor: #0000ff (sRGB)
    NSColor: #ffffff (sRGB)
    NSFont: Times-Bold 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #ffffff (sRGB)
    NSStrokeWidth: 0
[ ]
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[WebKit]
    NSColor: #0000ee (sRGB)
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSLink: https://webkit.org/
    NSStrokeColor: #0000ee (sRGB)
    NSStrokeWidth: 0
    NSUnderline: true
[.\n]
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[this is a ]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[t]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Italic 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
    NSUnderline: true
[est]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
    NSUnderline: true
[ of ]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[attributed]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Italic 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[ string.]
    NSBackgroundColor: #ffff00 (sRGB)
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0
[ ]
    NSFont: Times-Roman 16.00 pt.
    NSKern: 0pt
    NSStrokeColor: #000000 (sRGB)
    NSStrokeWidth: 0