PHP Vs. JavaScript: Which is Better and When to Use?

You will come across many languages, frameworks, and tools on your path to becoming a Web Developer. While exploring your options, you might have come across JavaScript and PHP. JavaScript and PHP power many of the websites we see on the internet. To give you an idea of their importance, many developers consider JavaScript and PHP to be the core of any website or web application.

To better understand the role of JavaScript and PHP in Web Development, let’s look deeper into their use cases, pros, cons, similarities, and differences. We will go through each language and clear up any confusion. This will ultimately help you decide which side to take on in PHP vs. JavaScript debate.

What is JavaScript?

JavaScript (short for JS) is a lightweight scripting language that enables you to make interactive and dynamic web pages — ever come across a cool-looking, flashy website with moving stuff? JavaScript does that. With JavaScript, you can create a dynamic website  – spice up your site with 2D and 3D animations, update page content in real-time, add interactive maps, and so much more. Alongside HTML and CSS, JavaScript is one of the three core technologies of the internet.

How JavaScript Works?

But how does JavaScript work? What happens when a webpage with JS gets loaded?

Let’s have a look at how JS works behind the scenes.

Source Code:

The “code” we write using any text editor (like VS Code) is known as source code. We write it by following a set of rules set by the language. It is not understandable by the machine and needs to be converted into a machine-readable format.

Runtime Environment:

Now that we have written our code. We need it to execute. But where can we execute it? The place or a “container” where our code can execute is known as a runtime environment.

In most cases, the runtime environment is one of these two:

• Browser (Edge, Firefox, Chrome, etc.)
• Node.js (Allows executing JS without a browser. Commonly used in Servers.)

Engine:

We have a runtime environment. Now it is time to execute our code. But wait, how can a machine understand our code? We need it to convert into a machine-readable format. That is precisely where an Engine comes in. It transforms our code into a form that the machine understands. 

Many JS Engines are available, with most browsers having their own versions.

Some of the most common JavaScript engines are

• V8  – Used By: Google Chrome
• Tampermonkey  – Used By: Mozilla Firefox
• Chakra  – Used By: Microsoft Edge.

To understand how a JS Engine works, we can break it down into the following parts:

• Parser (Input: Source Code, Output: AST)
• Abstract Syntax Tree (AST)
• Interpreter (Input: AST, Output: IR)
• Profiler (Optimizations)
• Compiler (Input: IR, Output: Machine Bytecode)

Parser:

So we have written our code, but how can the machine know it is correct? That is where the Parser comes into play. Knowing JS syntax, it goes through our code line by line, ensuring everything is right and according to JS syntax. 

Once everything looks good, it converts the code into Abstract Syntax Tree (AST for short).

Abstract Syntax Tree:

The parser represents your code as a tree. That “tree” is what we call AST. The main reason AST is made is that converting an AST to machine code is much easier than regular source code.

Interpreter:

The interpreter takes the AST and converts it into Immediate Representation (short for IR). IR is basically an abstraction of machine code.

Why we convert the AST into IR mainly due to the following reasons:

• Easier Optimization  – It is much easier to optimize IR than machine code.
• Adaptability  – IR can easily be converted into platform-dependant machine code.  

Profiler:

An essential of any website is its speed and performance. You wouldn’t want to visit a slow and unresponsive site, would you? A profiler optimizes the code, increasing its performance.

Compiler:

The compiler then takes the optimized IR. It converts it into machine code, which the machine can execute.

Execution:

The engine outputs machine-readable code, which can then be executed in the JS Runtime.

Do Developers Like JavaScript?

Fortunately, JavaScript has some extraordinarily good parts. In JavaScript, there is a beautiful, elegant, highly expressive language that is buried under a steaming pile of good intentions and blunders.

Douglas Crockford

According to the Stack Overflow Developer Survey 2022, 61.46% of JS developers love JS. Other than that, 12.98% of the non-JS developers expressed interest in learning JS.

Based on these stats alone, we can see that JS has an overall positive rep among developers.

Let’s look at some of the features JS developers love:

• Simplicity  – Easy to grasp and understand
• Accessibility  – Can deploy applications on any platform.
• Extendable  – A large number of frameworks to add more functionality.
• Flexibility  – Can be used for both front and backend.
• Active Support  – With ES6, many of its problems were fixed.

As for its shortcomings:

• The lack of Classes  – Makes switching to an Object-Oriented language tougher.
• Inconsistent Performace  – Has different performance on different browsers/runtimes.
• Loosely Typed  – This can cause problems in maintenance later on.

What is JavaScript Used For?

To better understand what you can use JS for, let’s look at some of the things you can make using JS.

• Interactive Webpages  – You can easily create a cool-looking, dynamic, responsive webpage that responds to every user’s click and touch.
• Websites and Web apps – Create a website about your product, startup, or personal portfolio. Create an application to manage your business,  handle customers or enhance your productivity. Choose from the many available frameworks, such as React, Angular, Vue, and many more.
• Web Servers – Develop and deploy your very own server using Node.js.
• Game Development – Develop creative and fun games and quickly deploy them to any website.

Okay, so JS is fancy and all, but what can it do that PHP cannot? Let’s have a look.

• Full-Stack Language – JS is full-stack, while PHP is only for server-side development.
• General Usage – JS is suitable for almost any type of project. In contrast, PHP is more suitable for blogs, management systems, and e-commerce websites.
• Performance – JavaScript is more performant as compared to PHP. This is so most of the asynchronous nature of JavaScript.
• Flexibility – JavaScript can be easily combined with other languages (HTML, XML, Ajax). PHP, on the other hand, can only be combined with HTML.

What is PHP?

I’ve never thought of PHP as more than a simple tool to solve problems.

Rasmus Lerdorf, Creator of PHP

Hypertext Preprocessor (Short for PHP) is an interpreted, open-source language used mainly for handling server-side operations. Used widely in Web Development, PHP is used in 77.5% of surveyed websites incorporating server-side functionalities. It performs many critical server-side tasks, such as handling database operations, updating dynamic content, and session-tracking. Additionally, you can use PHP with front-end frameworks like Laravel.

How Does PHP Work?

Let’s break down how PHP works behind the scenes as we did with JavaScript.

Source Code

Source Code is the “code” we write following the set of rules set by PHP. Humans can read it, but machines can’t. That is why we must convert it to a suitable format for the machine to read and execute our code. 

Engine

The engine takes the code we have written. The Engine aims to transform the source code into a machine-readable format.

PHP 7.0 uses PHPNG Engine instead of the old Zend Engine 2.0. The newer engine provides a significant boost to PHP’s performance.

The essential processes happening in the Engine are as follows:

• Lexing / Tokenization
• Parsing
• Compilation
• Optimization
• Caching

Lexing / Tokenization:

The first step in an Engine is passing the source code we wrote through a Lexer. What the lexer does is tokenize our source code. Now you might wonder what lexer and tokenization are. Well, think of the lexer as something that simplifies the code we wrote into simpler words. The “simple words” are known as tokens.

The tokens are created so that they can be read by the parser, who can then pass it to the compiler if all looks good.

Parsing:

The tokens created by the lexer are passed to a parser. The parser’s job is to ensure that the code we wrote is correct, according to PHP’s syntax.

An AST (Abstract Syntax Tree) is generated if everything looks good.

Compilation:

The compiler takes the AST generated by the Parser and translates it to low-level Zend opcodes. 

Optimization:

 Optimization is done to increase performance. Different algorithms transform the opcodes into other but equivalent instructions, which consume fewer resources and are faster.

Caching:

 Another way to improve performance is by caching instructions that have already been compiled. This eliminates the need to re-compile instructions if they have already been compiled before.

Execution:

After the compilation stage, the opcodes are executed in the Zend Engine’s VM. All of the instructions run from here. Tasks include handling, sending, and receiving data from and to the server.

Do Developers Like PHP?

PHP as an object oriented programming language should be judged by how well it does the job, not on a preconceived notion of what a scripting language should or shouldn’t do.

Peter Lavin, Object Oriented PHP

 According to the StackOverflow Developer Survey 2022, 58.39% of PHP developers dread the language.

Based on these stats, we can see that PHP has a not-so-positive rep among developers in 2022.

The disdain is not universal. Many still commend the language. As to why some developers still recommend PHP:

• Beginner Friendly – Easy for a beginner to understand
• Scalability – PHP is easily scaleable. This is especially important for startups and businesses looking to handle a large user base.
• Portable – Can be quickly shipped with almost any application (Wamp, PHP Desktop, etc.).
• Integrated Database Support – Supports databases like MYSQL, SQLite, and ORACLE out of the box.
• Affordable Hosting – Cheap rates when it comes to hosting a server.

As for why developers might not like PHP:

• Lack of Performance – PHP suffers in terms of performance in some instances. An example would be a large amount of I/O operations.
• No Asynchronous Support – PHP, out of the box, does not support asynchronous calls.
• Inconsistent Syntax – The syntax of PHP is sometimes said to be “sloppy.” Multiple naming conventions are used to name built-in functions.
• Vulnerable – PHP has a loose structure. This sometimes leads to insecure code, which is not up to industry standards. Which, in turn, makes the application vulnerable to malicious attacks.

Why do we use PHP instead of JavaScript?

Now you might be wondering why PHP developers still use such a language. Despite the negative feedback, we can see that PHP is still evolving. Many complaints were addressed with the announcement of PHP 7 and PHP 8.

One of the most notable examples can be the increase in performance. PHP 7.0 ditched its old Zend Engine 2.0 for the newer PHPNG Engine, which has dramatically increased PHP’s performance. Other than that, numerous vulnerabilities and security issues were also addressed. 

With a language so old and used on the Web, it is hard to let go. Stats show that almost 43% of websites are based on WordPress. WordPress, in turn, uses PHP. This shows just how much of an impact PHP has on the Web. It may be declining, but it will be around for quite some time.

PHP Vs. JavaScript: Similarities

 First, let’s have a look at some of the things which PHP and JavaScript have in common.

Weakly Typed

Both JavaScript and PHP are weakly typed languages. When declaring variables, we don’t have to write what their data type may be.

$x = 'Weakly Typed!';

$y = 'Don't need no types!';

var x = 'Hello World!';

let y = 'I am weakly typed too!';

Classes & Objects

Both languages did not support classes when they first came out. But over time, support for classes and objects was added.

class Person
{
// Properties

public $firstName;
public $lastName;
public $DOB;

// Constructor

// takes 3 arguments

function __construct($fn, $ln, $dob)
{
  $this->firstName = $fn;
  $this->lastName = $ln;
  $this->DOB = $dob;
}

// Get DOB

function get_dob()
{

  return $this->DOB;
}
}

class Person
{

// Constructor
// Takes 3 args
constructor (fn, ln, dob)
{
  // Properties inside constructor
  this.firstName = fn;
  this.lastName = ln;
  this.DOB = dob;
}

// Get DOB
get_dob()
{
  return this.DOB;
}

}

Dynamic Typing

Another similarity is that the variables in both languages are dynamically typed. This means we can change the data type of a variable later in the code after its declaration.

$x = 1; // Number

$x = 'String'; // Now a string 

var x = 'Hello World!'; // String

x = 1; // Now a number

Other similarities include the following:

Interpreted Languages – Both JS and PHP are known as “interpreted languages.” Their executions are done in their separate runtime environments.

Wide Usage – JS and PHP make up most of the internet. Almost any website you see on the internet uses JS or PHP in some way. This is great because both languages work well with each other. Countless frameworks exist for both languages, from Laravel to React.

PHP Vs. JavaScript: Differences

There are plenty of differences between PHP and JavaScript. Some of these include:

Syntax

Case Sensitive – PHP is not case sensitive except for variables. JS, on the other hand, is fully case-sensitive.

$x = 1; // First Variable
$X = 2; // Second Variable

echo $x // Works
eChO $x // Still works

var x = 'Hello World!'; // String

console.log("Hello"); // Works
console.log("Hello"); // Doesn't Work

Concatenation – In JS, you perform concatenation and addition using the “+” operator. In PHP, concatenation is done using “.” and addition using the “+” operator.

$x = 1; // First Variable
$y = 2; // Second Variable
$z = 'Hello';

echo $x + $y; // 3, addition
echo $z.' World'; // Concatenation

var x = 1;
var y = 2;
var z = "Hello";

y = x + y; // Add
z = z + " World"; // Concatenate

References – In JS, you can make references using the “.” operator. In PHP, “->” is the equivalent.

$class->method() // Function call

class.method() // Function call

Variables – In PHP, “$” indicates a variable. JS does not have such a convention.

$x = 2;

echo $x // Print x

var x = 2;

console.log(x); // Print x

Server-Side VS Client-Side – One of the most commonly discussed points in the PHP Vs. JavaScript debate is the nature of both languages. PHP is a server-side language, designed for handling operations and requests between various backend components. On the other hand, JavaScript leans to the client-side. JavaScript handles everything happening on the user end, and is mainly a front-end language, although you may use it for backend via Node.

 Although they are different, JavaScript also supports server-side scripting using Node.js.

Which is Better: PHP Vs. JavaScript?

If you are still wondering which one you should choose for your next project, here are a few things that can help you make the right decision. Let’s go through both of these languages one by one.

Consider PHP for your next project if you:

• Want to incorporate Databases such as SQL, Sybase, PostgresSQL, MariaDB, etc.
• Want to use CMS solutions such as WordPress, Joomla, Drupal, etc.
• Want to use the LAMP stack (Linux, Apache, MySQL, PHP)

While keeping in mind the pros and cons:

Pros:

• Faster Application Development
• Easier maintenance
• Easier to work with Databases
• Efficient workflow

Cons:

• Performance issues
• No Asynchronous Support 
• Vurnelable (Like the famous PHP SQL injection)

Consider JavaScript if you:

• Want to use awesome front-end frameworks such as Ember.js, Angular.js, React.js, etc.
• Are interested in creating dynamic web applications.
• Want to use frameworks such as Express.js, Node.js, etc.
• Want to use the MERN stack (MongoDB, Express.js, React.js, Node.js).

Having the following pros and cons:

Pros:

• Beginner Friendly
• Rich Interface
• High Performance
• Interoperable
• Versatile

Cons:

• Single Inheritance only
• Browser support issues
• Weak Client-side security.

If we look at it broadly, we can conclude that PHP is better for projects which involve CMS (Content Management System), such as WordPress. While JavaScript is better for full-stack web apps. JavaScript frameworks such as React and Vue are great for making full-stack web apps.

PHP Vs. JavaScript: Final Thoughts

Which language comes out on top in the PHP Vs. JavaScript debate? Well, there is no single definite answer. Each language has its strengths.

JavaScript shines in the front-end realm. Need anything flashy to impress your customers? JavaScript is the best solution. For anything related to the front end, JavaScript will handle it easily if you want to create an efficient, scaleable website catering to a large user base. PHP should be your best option. PHP makes server-side operations as well as handling data easier.

We have already seen that PHP could be doing better in popularity in 2022. One might wonder if JavaScript has what it takes to replace PHP. Well, this possibility does not seem like a far reality, as with Node.js, we can already handle the server side. In the near future, JavaScript could replace PHP entirely. But right now? PHP is such an integral part of the web that it will stay for quite some time, and the PHP vs. JavaScript battle will rage on.