PHP Introduction

When a user accesses a web page, there are two aspects to it. The first one is the user interface which delivers the user has requested information in a structured and lucid manner. What the user can see on the web page is called the ‘Front-end’. On the other hand, when the user enters a request into the web page, the web page, in turn, transfers the request to the server-side. The server side creates the backbone of the website. It is responsible for obtaining the relevant information either from the DNS server or from the database. This is called the ‘Back-end’.

PHP (i.e., Hypertext Pre-Processor) is a server-side scripting language that is also free and open-source. It is widely used because of its simplicity.

It is used to develop Web Applications (an application, i.e., executed at the server-side and generates the dynamic page.)

Learning PHP can be both easy yet challenging. However, we assure you that if you follow the step-by-step modules given on our website, you will be able to grasp the language within no time!

Index

What is PHP?

PHP stands for “Hypertext Pre-processor.”
Earlier stood for “Personal Home Pages.”
It is a server-side scripting language.
PHP is open-source and free.
PHP is an interpreted language.
PHP is used to develop static and dynamic webpages, web applications and is well suitable for web development
To execute PHP code, we need a Web server on which PHP must be installed.
PHP is Case Sensitive
It was designed to work with HTML pages. A block of PHP code can be embedded in the HTML page or be linked to it using an external ‘.php‘ file.
```
<HTML>
  <?php 
    //php code 
  ?>
</HTML>
```

We can create the PHP files without any HTML tags, and those records are called Pure PHP files.
The server processes the PHP code and outputs the result as HTML code to the web browser.

Why Learn PHP?

PHP can do anything related to server-side scripting or more popularly known as the back-end of a website. Some of the compelling reasons to work with PHP are listed below.

It is Open Source and Free, so you can freely download, install, and start using it for developing your web applications.
PHP is straightforward and easy to understand. The learning curve of PHP is smaller when compared to other server-side scripting languages.
It is Cross-Platform. So, you can quickly develop and deploy your PHP project to all the operating systems like Windows, Linux, Mac, etc.
It is fast compared to other programming languages.
PHP has in-inbuilt support for MySQL, which is one of the most widely used database management systems. That does not mean you cannot use PHP with other database management systems. You can still use PHP with Postgress, Oracle, MSSQL Server, ODBC, etc.
With PHP, you can design static and dynamic webpages.
PHP has lucid support when it comes to file handling, sending emails, accessing and modifying cookies, creating sessions, and receiving data from forms and storing the data in a database.
You can easily add, delete, and modify elements within your database through PHP.

Preconditions for Starting With PHP

PHP can be learned as a separate language. However, if a developer plans to implement it for web development, then, in that case, it is beneficial to have a basic knowledge and understanding of HTML, CSS, and JavaScript.

PHP Versions:

Every two years, a new PHP version is launched with better gains in performance and bug fixes. In the latest versions, 7.2, 7.3, 7.4, and 8.0, many additional in-built tools have been provided, along with better support. Presently, to identify the PHP files and scripts, we must use the file extension, “.php”.

Some of the Older PHP file extensions are mentioned below which are no longer valid.

.phtml
.php3
.php4
.php5
.phps

Difference between PHP 5 and PHP 7

There is was nothing explicitly wrong with PHP5. However, the developers and the users noticed the website’s dipping speed and performance on using PHP5 as the server-side scripting language. Many discussions took place about PHP 5.7, PHP 6, and PHP 7: however, PHP 6 never reached a steady version. So, the PHP community chose to shift from PHP 5.6 to PHP 7. The pre-loading time is significantly less in PHP 7, which instantly hit the developers. Therefore, we suggest you upgrade to PHP 7 if you are using an older version of PHP.

The fantastic features of PHP 7 have increased its popularity among developers. Businesses should choose to enhance their websites by upgrading from PHP 5 to PHP7 as it would enhance the response time of web pages and help the customers to have better UI/UX. Ultimately, PHP7 would tremendously increase the productivity of the business.

Some of the Main Points

Performance: It is evident that later versions are always better than the previous versions. So if you can execute your code in both versions, you will find the performance of PHP 7 is better than PHP 5.
Return type: In PHP 5, the programmer is not permitted to define the return value of a function, which is the drawback of PHP 5. However, in PHP 7, this limitation is overcome, and a programmer is to define the return type of function.
Example
```
public function area (float $r) : float{
  return 3.14*$r*$r;
}
```
Error Handling: In PHP 5, it was challenging to manage fatal errors, while in PHP 7, the significant errors are replaced by exceptions, which can be handled easily. In PHP 7, the engine exception objects have been introduced.
64 Bit Support: PHP 5 does not support 64-bit integers, while PHP 7 supports 64-bit integers and larger files.
Anonymous Class: The Anonymous class is a new addition in PHP 7. When you need to execute the class only once to increase the execution time, it comes into the picture.
New Operators: Some new Operators have been added to PHP 7, such as < = >, which is called a three-way comparison operator. Another operator has been added, called a null coalescing operator, whose symbol is ‘??’. It is used to replace the ternary operation in conjunction with the isset() function. The null coalescing operator returns its first operand if it exists and is not NULL; otherwise, it returns its second operand.
Example: Three way Comparision operator
Earlier
```
function sort ($a,$b){
  if ($a>$b)
    return 1;
  else if ( $a ==$b)
    return 0;
  else
    return -1;
}
```
In PHP7
```
function sort ($a,$b){
  return $a < = > $b;
}
```
Example: Null coalescing operator
Earlier
```
if (isset ($_GET [‘name’])){
  $name = $_GET [‘name’];
}else{
  $name = null;
}
```
In PHP7
```
$name = $_GET [‘name’]?? Null;
```

PHP in Terms of Market Share

There are over a million websites and applications on the internet which are developed using PHP. It accounts for the marketing of 79.2% amongst all the server-side languages.

The given chart depicts some of the famous sites that use PHP.

Flowchart

The flowchart diagram below gives a basic idea about PHP’s underlying architecture and how the server handles the PHP requests.

Read More: Complete PHP Installation Guide

Conclusion

PHP is an excellent tool for writing dynamic web pages. Non-technical users or amateur developers can quickly learn tricks to make their web pages easier to manage and use.

We hope you have enjoyed reading about PHP from a general perspective. If you want to dive deeper into this dynamic language, make sure to follow our easy-to-comprehend PHP Tutorial.