PHP string--Encoding and escaping

The function htmlentities () converts HTML characters to corresponding entities (except for whitespace). Includes less than symbol (<), greater than sign (>), ampersand (&), and accented characters.

function Htmlspacialchars () transforms the smallest set of entities to generate legitimate HTML

and symbols (&) are converted into &amp;
Double quotation marks (") are converted into &quot;
Single quotation marks (') are converted to & #039;(like the effect of using ent_quotes when calling Htmlentities ())
The less than sign (<) is converted into &lt;
The greater than sign (>) is converted into &gt;

PHP string--Encoding and escaping