> ## Documentation Index > Fetch the complete documentation index at: https://docs.fydemy.com/llms.txt > Use this file to discover all available pages before exploring further. # PHP Learning backend development with PHP is one of the best ways to understand how websites work behind the scenes. Unlike frontend which is visible directly in the browser, PHP runs on the **server** and generates HTML that gets sent to the user. This section is designed to be simple and straight to the point — don't worry if some parts feel confusing at first, that's completely normal. ## Prerequisites * Download an IDE from this link: [VSCode](https://code.visualstudio.com/download) * Install PHP and a local web server. You have two options: * **XAMPP** — [Download here](https://www.apachefriends.org/download.html). Includes Apache + PHP + MySQL. After installing, open the XAMPP Control Panel and start **Apache**. * **Laragon** — [Download here](https://laragon.org/download/). A lightweight and modern alternative, recommended for Windows users. Just install and click **Start All**. ## Let's get started ### Open a project All PHP files must be placed inside the correct web server folder so they can be run in the browser. **XAMPP** * Windows: `C:\xampp\htdocs\` * Mac/Linux: `/Applications/XAMPP/htdocs/` **Laragon** * Windows: `C:\laragon\www\` Create a new folder there — for example name it `learn-php`. Then open that folder in VSCode via **File > Open Folder**. ### Create a new file Click the add-file icon in the sidebar, then type `index.php`. Press Enter to create it. The file structure of a PHP project generally looks like: * **PHP** `*.php` — server logic, fetching data, processing forms, generating HTML * **HTML** `*.html` or inside `*.php` — the content users see on the page * **CSS** `*.css` — styling for HTML elements For example: * PHP fetches data from a database (who is logged in, what products are available) * HTML displays that data on the page * CSS makes it look clean and organized ### Run the project Open your browser and go to: **XAMPP** ``` http://localhost/learn-php/ ``` **Laragon** ``` http://learn-php.test/ ``` The browser will automatically load `index.php`. *** ## PHP ### Comments ```php theme={null} // This is a single-line comment # This is also a single-line comment /* This is a multi-line comment */ ``` Anything inside a comment is not executed by the program — it's only for notes so you (or others) can understand the code. ### PHP Tags PHP code is always written between an opening and closing tag: ```php theme={null} ``` You can mix PHP and HTML inside a single `.php` file: ```php theme={null} My First Page

``` `echo` is used to output content to the page. ### PHP file structure ```php theme={null} Personal Portfolio

Hello, !

``` *** ## CSS Just like in plain HTML, you can use CSS to style your page. There are **3 ways** to do it (the 2nd is recommended): **1. Inline CSS (attribute)** Easiest, but not recommended — it clutters your HTML when styles get complex. ```html theme={null}

Welcome!

``` **2. External CSS (recommended)** Create a new `style.css` file and link it from your PHP file. This is the best approach as your project grows. **index.php** ```php theme={null} Personal Portfolio

Hello!

``` **style.css** ```css theme={null} .header { text-align: center; } ``` **3. Internal CSS** Write CSS inside a `

Hello!

``` *** # Systematic thinking How can human logic be expressed in code? PHP can do it! Let's get familiar with the fundamentals. ## PHP Programming Concepts ### Variables Variables in PHP always start with a **`$`** sign. ```php theme={null} ``` **Naming rules:** * Always start with `$` * No spaces — Wrong: `$full name` * Use camel case — Correct: `$fullName` * Or snake case — Correct: `$full_name` ### Data Types **String** — text, wrapped in quotes. ```php theme={null} $text = "Welcome"; ``` **Integer** — whole numbers. ```php theme={null} $year = 2025; ``` **Float** — decimal numbers. ```php theme={null} $score = 98.5; ``` **Boolean** — only `true` or `false`. ```php theme={null} $isLoggedIn = false; ``` **Array** — holds multiple values in one variable. ```php theme={null} $items = ["joko", 19, true]; // Associative array (key-value pairs) $user = [ "username" => "john doe", "age" => 12, "married" => false, ]; ``` ### Conditionals **if / elseif / else** ```php theme={null} 30) { echo "Hope you find someone soon"; } else { echo "Hang in there!"; } ?> ``` **Logical operators** Say we have `$atSchool = false` and `$age = 3`: * `!$atSchool` — **!** is negation (the opposite). So this is **true**. * `$atSchool && $age > 1` — **&&** means "and". Both must be true for the whole expression to be true; if either is false, the result is **false**. * `$atSchool || $age > 1` — **||** means "or". If at least one is true, the result is **true**. ### Functions Functions in PHP use the `function` keyword. They can accept parameters and return a value with `return`. **Built-in functions** PHP has many built-in functions ready to use: ```php theme={null} ``` **User-defined functions** ```php theme={null} ``` *** ## Form & Interaction One of PHP's core strengths is processing **HTML forms**. The form is submitted to the server and PHP handles it directly — no extra code needed on the browser side. ### Sending data with a form **index.php** ```php theme={null} PHP Form
``` **process.php** ```php theme={null} ``` * `$_POST` — retrieves data from a form submitted with the `POST` method * `$_GET` — retrieves data from the URL (query string) * `.` — the concatenation operator, used to join strings together *** ## Dynamic Output PHP **generates HTML** on the server before sending it to the browser. This means the page content can change based on data — all without any extra code on the browser side. ### Loop to display data ```php theme={null} ``` The HTML output generated: ```html theme={null} ``` ### Include other files PHP can split a page into reusable components: ```php theme={null}

Page content

``` *** ## Ready? You now understand the basics! Let's put this into practice by building a real project. *** # Layouting For this project, you're expected to already understand the basics above. ## Level 1: Text Procedure Here you need to understand HTML concepts: list elements, headings, images, and CSS: layout, padding, and border. This is the layout prototype — good luck! ### Tips and requirements * You can use the `float` or `flex` property in CSS * Include images with `` — you can use a local file or a URL from the web * Use list elements in HTML, for example: ```html theme={null} ``` * List data can be stored in a PHP array and looped into HTML Level 1 layout ## Level 2: Portfolio Section with a Form Here you need to combine HTML (form/button), CSS (layout), and PHP (processing input). This is the layout prototype — good luck! ### Tips and requirements * Build a form with a name input, then display a welcome message after it's submitted * Match the layout exactly. You can use **flexbox** in CSS: ```html theme={null}
``` * Use `$_POST` to retrieve form data in PHP * Display data conditionally: ```php theme={null}

Hello, !

``` * Always use `htmlspecialchars()` when displaying user input — this prevents XSS attacks Level 2 layout Add your Github link or project in Google Drive then the community will review and help you together. Please stay tuned on Discord to see the latest updates!