<p dir="ltr">A comment is a part of the coding file that the programmer does not want to execute, rather the programmer uses it to either explain a block of code or to avoid the execution of a specific part of code while testing.</p>
<p dir="ltr">&nbsp;</p>
<h3 dir="ltr">PHP supports several ways of commenting:</h3>
<p dir="ltr"><strong>Single Line Comments</strong></p>
<pre class="language-php"><code>&lt;?php
// This is a single-line comment
# This is also a single-line comment
?&gt;</code></pre>
<p dir="ltr">&nbsp;</p>
<p dir="ltr"><strong>Multiple-Line Comments</strong></p>
<pre class="language-php"><code>&lt;?php
/*
This is a
multiple line
Comment.
*/
?&gt;</code></pre>
<p>&nbsp;</p>

PHP Comments

<p dir="ltr">PHP is a server-side scripting language, which is used to manage dynamic web pages, databases and build websites with features like session tracking and e-commerce. On a day of 1995, Rasmus Lerdorf unleashed the first version of &ldquo;Hypertext Preprocessor&rdquo; also known as the PHP language. It is also integrated with several popular databases like MySQL, PostgreSQL, Microsoft SQL Server, Oracle etc.</p>
<p dir="ltr">&nbsp;</p>
<h3 dir="ltr">Uses of PHP</h3>
<p dir="ltr">PHP can perform several system functions like opening files, CRUD operations on data stores, general-purpose scripting, etc. Besides system operations, there are also other uses like</p>
<ol style="list-style-type: lower-alpha;">
<li dir="ltr">Handling Forms: PHP can handle form operations. It can gather data, save data to a file and send data through emails.</li>
<li dir="ltr">Database Operations: PHP can also create, read, update and delete elements in your database.</li>
<li dir="ltr">Encryption: It can perform advanced encryption and encrypt data for you.</li>
<li dir="ltr">Dynamic Page Content: It can generate dynamic page content.</li>
</ol>
<p>&nbsp;</p>
<h3 dir="ltr">Basic Syntax PHP</h3>
<p dir="ltr">A PHP script can be written anywhere inside the HTML document. A PHP script starts with &lt;?php tag and ends with ?&gt;. We can write our logic inside this tag and it will be executed accordingly.</p>
<pre class="language-php"><code>&lt;?php
// PHP code goes here
?&gt;</code></pre>
<h3>Displaying output in php</h3>
<p>In php,Output is displayed on the browser using echo as follows:</p>
<pre class="language-php"><code>&lt;?php
echo "hello";
?&gt;</code></pre>
<h3 dir="ltr">Hello World</h3>
<p dir="ltr">A basic PHP Hello World program looks something like this. We will use a built-in PHP function &ldquo;echo&rdquo; to output the text &ldquo;Hello World!&rdquo; on our webpage.</p>
<pre class="language-php"><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;body&gt;
&lt;h1&gt;My first PHP page&lt;/h1&gt;
&lt;?php
echo "Hello World!";
?&gt;
&lt;/body&gt;
&lt;/html&gt;</code></pre>
<p>&nbsp;</p>

PHP Overview

PHP Conditional Statements

PHP Iterative Statements

PHP DataTypes

PHP Operators

Variables in PHP

Variable Scope

Include & Require 

File Handling

Arrays

Function Basics

Function Arguments

Introduction

Connecting to MySQL

Creating a MySQL Database

Creating Table in MySQL

Inserting Data in MySQL

Selecting Data in MySQL

Updating Data in MySQL

Deleting Data in MySQL

Introduction to OOPS

Classes

Objects

Inheritance

Constructors and Destructors

Access Modifiers

Interface

Abstract Classes

Class Constants

Traits

Static Methods

Static Properties

Superglobals

$GLOBALS

$_SERVER

$_REQUEST

$_POST

$_GET

$_COOKIE

$_SESSION