How can I insert div or img into textarea?

How can I insert div or img into textarea?

I'm trying to insert a div into textarea:
$(document).ready(function(){
$('#toclick').click(function(){
var text = '<div id="block"></div>';
$('#textarea').val( $('#textarea').val() + text);
});
});
<textarea id="textarea"></textarea>
<div id="toclick"></div>
But there's only HTML inside textarea instead of div. How to fix it?