hide scrollbar and use html tag in textarea

[itsource]

How to hide scrollbar of textarea and use html tag in textarea such as

<b>Test </b> and show Test in textarea?

[oblig]

Scrollbar question not possible, cannot apply a change in weight (i.e. bold) to just one section of text in a textarea. It's either all bold or not bold:

<textarea style="font-weight:bold">
</textarea>