You should use different methods for different use cases:
- If you want to emphasise a phrase, use
<em>
. - The
<i>
tag has a new meaning in HTML5, representing “a span of text in an alternate voice or mood”. So you should use this tag for things like thoughts/asides or idiomatic phrases. The spec also suggests ship names (but no longer suggests book/song/movie names; use<cite>
for that instead). - If the italicised text is part of a larger context, say an introductory paragraph, you should attach the CSS style to the larger element, i.e.
p.intro { font-style: italic; }