PHP · Theory

Form Handling

Theory

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If you can teach Form Handling using login form fields, you know it. If you only know the heading, you don’t.

Do Form Handling once by hand. $_POST['user'] after isset. Change one input. Say the new result out loud.

Form Handling exists so Asha can keep login form fields correct in login.php.

Use Form Handling when login form fields must stay clear. If a simpler PHP step works, use that instead.

Form Handling miss — no htmlspecialchars on output. Fix it before you talk about advanced PHP.

After Form Handling, Asha should still remember no htmlspecialchars on output.

Close Form Handling with — “If I skip it, login form fields goes wrong like this: no htmlspecialchars on output.”

Diagram

  Browser
      │ POST / GET
      ▼
   .php file
      │
      ▼
   HTML back

Exam tip

For Form Handling: definition + login.php + one failure.

<?php
// $name = $_POST["name"] ?? "";
$name = "Asha"; // demo input
$name = htmlspecialchars($name, ENT_QUOTES, "UTF-8");
echo "Hello, $name";

Form Handling — read request data carefully and escape output to prevent XSS.