Nope. Web browsers do not want you to be able to insert (actually validated) markup live in a page; it's a huge security risk. Some more info from someone far smarter than I is here:
As for what you're actually looking to do - take a look at the Markdown component. It supports, as the name implies, Markdown, a very limited formatting "language" that degrades gracefully to plain text but also allows custom hyperlinks, inline styling to a certain degree, etc.