PHP Syntax - PHP Tutorial

PHP scripts are executed on the server, and the result is sent back to the browser as plain HTML.

Basic PHP Syntax

PHP scripts can be embedded anywhere within an HTML document. They start with <?php and end with ?>.

<?php
// Your PHP code goes here
?>

By default, PHP files have the extension .php. Typically, these files contain a mixture of HTML tags and PHP code.

Example

Here’s a simple PHP file containing both HTML and PHP code:

<!DOCTYPE html>
<html>
<body>

<h1>Welcome to My PHP Page</h1>

<?php
echo "Hello World!";
?>

</body>
</html>

Note: PHP statements must end with a semicolon ;.

PHP Case Sensitivity

While PHP keywords (e.g., if, else, while, echo, etc.), classes, and functions are not case-sensitive, variables are case-sensitive.

In the example below, all three echo statements are valid and equivalent:

Example

<!DOCTYPE html>
<html>
<body>

<?php
ECHO "Hello World!<br>";
echo "Hello World!<br>";
EcHo "Hello World!<br>";
?>

</body>
</html>

However, variable names are case-sensitive. Consider the following example where only the first statement displays the value of the $color variable correctly:

Example

<!DOCTYPE html>
<html>
<body>

<?php
$color = "red";
echo "The car is " . $color . "<br>";
echo "The motorcycle is " . $COLOR . "<br>";
echo "The bicycle is " . $coLOR . "<br>";
?>

</body>
</html>

In this instance, $COLOR and $coLOR are considered different variables from $color.