htmlentities() vs. htmlspecialchars()

Question

What are the differences between htmlspecialchars() and htmlentities(). When should I use one or the other?

Answer 1

Because:

• Sometimes you're writing XML data, and you can't use HTML entities in a XML file.
• Because htmlentities substitutes more characters than htmlspecialchars. This is unnecessary, makes the PHP script less efficient and the resulting HTML code less readable.

htmlentities is only necessary if your pages use encodings such as ASCII or LATIN-1 instead of UTF-8 and you're handling data with an encoding different from the page's.