A PHP script is executed on the server, and the plain HTML result is sent back to the browser.
Basic PHP Syntax
A PHP script can be placed anywhere in the document.
A PHP script starts with
<?php and ends with
// PHP code goes here
The default file extension for PHP files is "
A PHP file normally contains HTML tags, and some PHP scripting code.
Below, we have an example of a simple PHP file, with a PHP script that uses a
built-in PHP function "
echo" to output the text
"Hello World!" on a web page:
<h1>My first PHP page</h1>
echo "Hello World!";
Note: PHP statements end with a semicolon (
PHP Case Sensitivity
In PHP, keywords (e.g.
echo, etc.), classes, functions,
and user-defined functions are not case-sensitive.
In the example below, all three echo statements below are equal and legal:
ECHO "Hello World!<br>";
echo "Hello World!<br>";
EcHo "Hello World!<br>";
Note: However; all variable names are case-sensitive!
Look at the example below; only the first statement will display the value of the
$color variable! This is because
$coLOR are treated as three
$color = "red";
echo "My car is " . $color . "<br>";
echo "My house is " . $COLOR . "<br>";
echo "My boat is " . $coLOR . "<br>";