Front-end and back-end practice for developers who own their own performance budget.
Escaping tries to neutralize dangerous characters. Parameterization removes the question by never letting data be parsed as code. Here is the difference, the PDO settings most tutorials skip, and the three places a placeholder cannot save you.
CSRF exploits one browser behavior: cookies are attached automatically, no matter who initiated the request. Tokens work because an attacker can make your browser send a request but cannot read your page to find the token. Here is the whole mechanism, with working PHP.
Five filters with four options each is 1,024 combinations, and a crawler will try to find all of them. Here is how faceted navigation turns into an infinite space, why rel=next/prev is not the fix, and the three patterns that keep pagination crawlable without the explosion.