About PHP
PHP is a programming language commonly used on web servers. It can generate HTML, handle submitted forms and work with databases to power dynamic websites and content-management systems.
- Dynamic websites
- Content management
- Server APIs
- Created by
- Rasmus Lerdorf
- First released
- 1995 · first public release
- Version / standard
- PHP 8.5
Current stable release line. Hosting providers may offer several supported versions.
In the real world
- WordPress: The WordPress content-management system
- Wikipedia: The MediaWiki platform behind the site
- Drupal: The Drupal content-management system
Facts checked 8 September 2026. Links open the sources; examples describe specific products or documented uses.
Syntax
$name = "Ada";
echo "Hello, $name";Examples
A small working example
Follow the values through this example, then change one input.
<?php
$name = "Ada";
$lessons = 3;
echo "$name completed $lessons lessons\n";Printing a greeting
A small, runnable example of this syntax.
<?php
$name = "Ada";
$count = 3;
echo "$name has $count messages.";
?>Best practices
- Use descriptive variable names and keep presentation templates separate from application logic as a project grows.
- Keep examples small while learning, then combine the idea with a real project.
At a glance
- Purpose
- Server-side web applications
- File extension
- .php
- Runs in
- PHP runtime on a server or CLI
- Usually used with
- HTML, databases and web servers
In plain English
PHP variables start with $. A variable can hold text, numbers or other values, and echo writes output.
What you’ll learn
- Assign a variable.
- Read a case-sensitive name.
- Interpolate text.
Breaking down the syntax
$name- A variable identifier.
=- Assignment.
echo- Writes one or more strings.
How it works
Input or value
Obtain the data.
Variable
Assign it to a meaningful name.
Output
Format the result for its destination.
When should I use this?
Name values in server-side request handling or command-line scripts.
Common mistakes
A common trap
Variable names are case-sensitive.
Incorrect
$name = "Ada";
echo $Name;Corrected
$name = "Ada";
echo $name;Compare approaches
- Single-quoted string: Mostly literal text.
- Double-quoted string: Variable interpolation and escape sequences.
Explore deeper
Output depends on context
When inserting untrusted text into HTML, encode it for the HTML context. Plain echo does not automatically make user input safe for a web page.