PHP in Practice

Uploaded : 3 months ago Updated : 3 months ago beginner

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Apply the fundamentals: you’ll handle a simple form submission — the bread and butter of PHP back ends.

Project: a contact form handler

Create an HTML form with method="post".
Point its action to a .php file.
In PHP, read the submitted fields from $_POST.
Validate them and show a confirmation.

The form (HTML)

<form method="post" action="submit.php">
  <input name="email" type="email">
  <button type="submit">Send</button>
</form>

The handler (submit.php)

<?php
$email = trim($_POST["email"] ?? "");

if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo "Thanks! We will reach you at $email";
} else {
  echo "Please enter a valid email.";
}

Always validate input

Never trust $_POST/$_GET data. Validate and sanitise everything — it is your first line of defence against attacks.

Good habits vs. common mistakes

Do ✓	Don’t ✗
Validate every input	Trust `$_POST` blindly
Use prepared statements for SQL	Concatenate user data into SQL
Use the `??` null-coalescing operator	Assume keys always exist
Show generic errors to users	Leak stack traces in production

SQL injection is the #1 risk

Never build SQL by concatenating user input. Use prepared statements (PDO/MySQLi) — frameworks like Laravel do this for you.

Talk is cheap. Show me the code.Linus Torvalds

What is $_POST?

A built-in array holding data submitted via an HTML form with method="post".

How do I connect to a database?

Use PDO with prepared statements, or an ORM like Laravel’s Eloquent.

What’s next after PHP?

Laravel — the most popular PHP framework, built on these foundations.

PHP in Practice

Project: a contact form handler

The form (HTML)

The handler (submit.php)

Good habits vs. common mistakes

Keep going

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