When would you use htmlentities?

HTMLENTITIES disallows users to run malicious code in HTML.
The htmlentities function takes a string and returns the same string with HTML converted into HTML entities.
Syntax:
htmlentities(string,quotestyle,character-set)
String – string to be converted.
Quotestyle- optional parameter that defines how to encode single and double quotes.
Character-set – Optional parameter that specifies the character set.