Home Course PHP Syntax

PHP Syntax

by MH RISHAD - 20 Oct 2018

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  and ends with ?>:

// PHP code goes here

The default file extension for PHP files is ".php".

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:

First PHP Page

echo "Hello World";


 Note: PHP statements end with a semicolon (;).

Comments in PHP

A comment in PHP code is a line that is not read/executed as part of the program. Its only purpose is to be read by someone who is looking at the code.

Comments can be used to:

  • Let others understand what you are doing
  • Remind yourself of what you did - Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code

PHP supports several ways of commenting:


// This is a single-line comment

# This is also a single-line comment

This is a multiple-lines comment block
that spans over multiple

// You can also use comments to leave out parts of a code line
$x = 5 /* + 15 */ + 5;
echo $x;


PHP Case Sensitivity

In PHP, all keywords (e.g. if, else, while, echo, etc.), classes, functions, and user-defined functions are NOT case-sensitive.

In the example below, all three echo statements below are legal (and equal):

ECHO "Hello World!
echo "Hello World!
EcHo "Hello World!


 In the example below, only the first statement will display the value of the $color variable (this is because $color, $COLOR, and $coLOR are treated as three different variables):

$color = "red";
echo "My car is " . $color . "
echo "My house is " . $COLOR . "
echo "My boat is " . $coLOR . "


Thank You 



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