PHP Fundamentals

PHP Introduction

PHP does its work on the server, behind the scenes, before any HTML ever reaches the visitor's browser — it's the difference between a static page and one that can actually think.

Variables & Data Types

A PHP variable is a labeled box you can put a value into — it always starts with $, and PHP figures out what kind of value is inside without you ever having to say so.

Control Structures

if/else lets your code make decisions, and for/while/foreach let it repeat itself — the two ingredients almost every useful program is built from.

Functions & Arrays

A function lets you name a set of steps once and reuse it forever after; an array lets you hold many related values under a single name instead of juggling separate variables.

Working with Forms ($_GET and $_POST)

When a form is submitted, PHP automatically hands you the submitted values in a superglobal array — and every single value that comes from a visitor has to be treated as untrusted until proven otherwise.

Sessions, Cookies & Security Basics

The web forgets everything between page loads by default — sessions are how PHP gives each visitor a bit of memory, and a few simple habits now will save you from the most common beginner security mistakes later.

Object-Oriented PHP Basics

A class is a blueprint, an object is one thing built from it — bundling related data and the functions that act on it together, instead of keeping them as separate loose variables and functions.

Working with Dates and Times

PHP has both a quick, function-based way to work with dates (date()) and a fuller object-oriented one (DateTime) — knowing when to reach for each will save you a lot of headaches once your app needs to handle real calendar dates.

String Functions in Depth

PHP ships with a huge library of ready-made functions for slicing, searching, and reshaping text — knowing a handful of common ones well will save you from writing character-by-character loops for problems PHP has already solved.

Reading and Writing Files

Sometimes data needs to live in a plain file on disk rather than a database — PHP's file functions let you read, write, and append to files, though a few small habits keep this power from causing quiet data loss.

Error Handling with Try/Catch

Not every problem in a program can be prevented in advance — try/catch lets your script notice when something goes wrong at runtime and respond deliberately, instead of crashing outright or failing silently.