It seems you can't put markup into a textarea or input field. But you could always make something look like a text area.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>This is not a text box.</title>
border: 3px inset #fff;
<p>This is <em>not</em> a text box.</p>
<p>No really, it <em class="mega">isn't</em>.</p>
Disclaimer. (1) Whilst I will help you sometimes, if I feel like it, and my advice in relation to your actual question will be of good quality: my posts are to be taken with a pinch of salt. I will be sarcastic, deploy irony and include obscure cultural references for my own amusement without warning.
(2) You will gain nothing from complaining, and if you try to argue with me then you will not win. No matter how noble your battle seems, I am still better than you, don't be an hero.