How to protect the site from hacking on a GET request?

Question

PHP

How to protect the site from hacking on a GET request?

Answer 1

$var_name = htmlspecialchars(trim(strip_tags(stripslashes($_POST['var_name']))));
$var_name = htmlspecialchars(trim(strip_tags(stripslashes($_GET['var_name']))));

Answer 2

Don't defend at all.
There are no "hacks" on a "GET request" in nature.

Answer 3

Everything that came from the user must be immediately run through the regular expression (filter) to determine the presence of "left" characters and that's it.