HTML code for an apostrophe

Question

Seemingly simple, but I cannot find anything relevant on the web.

What is the correct HTML code for an apostrophe? Is it ’?

Answer 1

Even though ' reads nicer than ' and it's a shame not to use it, as a fail-safe, use '.

' is a valid HTML 5 entity, however it is not a valid HTML 4 entity.

Unless is at the top of your HTML document, use '