What are some common issues that can arise when using htmlentities in PHP?

One common issue that can arise when using htmlentities in PHP is that it may not properly handle encoding certain characters, leading to potential security vulnerabilities such as cross-site scripting (XSS) attacks. To mitigate this issue, it is recommended to use the ENT_QUOTES flag with htmlentities to encode both double and single quotes.

// Using htmlentities with ENT_QUOTES flag to encode both double and single quotes
$encoded_string = htmlentities($string, ENT_QUOTES);