Text formatting in JS alerts

Question

How can I print a value (defined by Users input) in an alert strong, italic and red?

Answer 1

You should be able to don't forget you can add "<h1>" and "<p>" tags.

Answer 2

but this is not working.
What should I change, if I want to print the Users name bold and italic?

alert ("Hello " + document.getElementById('username').value +"!")