PHP vs JavaScript—what’s the difference? The answer to that question used to be incredibly simple: JavaScript is a client-side script, and PHP is a server-side script. Together they make the dynamic web pages that we know and love possible. However, with the introduction of Node.js in 2009, which allowed JavaScript to be used on the server-side, JavaScript-powered applications took off and the question of choosing between the two languages became more viable. Let’s explore the key similarities and differences between these two languages.
What is PHP?
PHP (Hypertext Preprocessor) is a general purpose scripting language that quickly became the de facto server-side language of choice for web developers after its initial release in 1995. Today, a majority of sites on the web run on PHP, due in large part to its popularity as the back-end of content management systems (CMS) like WordPress, Drupal, and Joomla. Whether it’s for a simple blog or a small business owner looking to set up a professional landing page, a CMS is usually the quickest, cheapest way to set up an online presence.
What is JavaScript?
Alongside HTML and CSS, JavaScript (standardized as ECMAScript) is considered one of the big three core components of the web. Employed by a majority of websites, JavaScript is a scripting language that typically runs in the browser and makes web pages dynamic and interactive. Today, JavaScript is also quickly growing as a server-side technology since the release of Node.js in 2009.
PHP vs JavaScript: Major Similarities
As different as they are, there are some top-level similarities worth considering, especially if you are comparing a PHP back-end to Node.js.
- Interpreted. Both PHP and JavaScript are what you call interpreted languages, or “scripts”—the code can be run as-is in their respective runtime environments (browser for JavaScript; server for PHP). While there’s a lot of nuance to the compiled vs. interpreted debate, it is generally true that scripts are much easier to use and favor programmer productivity. Both PHP and JavaScript fall into this category and are great for beginners and veterans alike.
- Ubiquitous. Together, both PHP and JavaScript power a majority of websites. For most of their existence they were like peanut butter and jelly—JavaScript on the front-end, PHP on the backend. That means there is a huge codebase of libraries, frameworks and community support for these two languages together as a package deal. Think of an idea or a question and it’s likely somebody, somewhere has already developed a solution.
PHP vs JavaScript: Major Differences
For many developers, the answer is obvious—JavaScript is the undisputed king of front-end web development, and PHP is the most popular server-side script. With that in mind, in this section we’ll compare Node.js, JavaScript’s foothold on the client-side, with a PHP back-end.
- Runtime Environments. There’s a reason JavaScript is almost synonymous with client-side scripting while PHP has largely remained on the server-side. While both can be embedded directly into HTML, they both need an interpreter in order to run. JavaScript’s interpreter is built into all the major web browsers because it is such a core component of the web experience. PHP interpreters have long been easily installed into popular servers like SQL as a simple plugin. Node.js was a game changer because it allowed JavaScript to come over to run on the server-side, but before 2009, its use was largely considered to be restricted to front-end development.
- Simplicity. PHP is conceptually much simpler to use than Node.js. When setting up a server, all you need is a “.php” file with some code wrapped between the
<?php ?>tags, enter the URL into your browser, and you’re done. The statement you wrap between those tags can be as simple as<?php echo ‘Hello World’; ?>and it will work. Behind the scenes, a web server like MySQL with PHP installed will be able to interpret the file and display your web page in your browser. Setting up a Node.js server, while not difficult, usually requires more lines of code, and a basic understanding of how closures and callback functions work. - Concurrency. PHP, like most server-side languages, uses multi-threaded, blocking I/O to carry out multiple tasks in parallel. JavaScript is unique in that it uses a few tricks (event loop + Node clustering) to achieve an event-driven, non-blocking I/O execution model that uses a single main thread of execution. PHP has been around the block for a while though, and has found its own way to achieve asynchronous processing—most notably through the HHVM project released by Facebook.
- JSON. JSON “JavaScript Object Notation” is a lightweight data format that is syntactically similar to JavaScript object definitions. Naturally, that gives Node.js- and JavaScript-based technologies an edge when dealing with JSON. While PHP can work with JSON, it’s more situational.
When Should You Use PHP or JavaScript?
Even with the advent of Node.js, the short answer to this question is still: JavaScript for the client-side, and PHP for the server-side. But, if you’re trying to choose between back-end technologies or are building an entire solution stack, it helps to go into a little more detail. You should consider PHP if your project involves…
- CMS’s like WordPress, Drupal, or Joomla etc.
- Servers like MySQL, SQL, MariaDB, Oracle, Sybase, and Postgresql etc.
- Solution Stacks like LAMP (Linux, Apache, MySQL, PHP)
You should consider JavaScript if your project involves…
- Dynamic single page applications (SPAs)
- Front-end technologies like jQuery, AngularJS, Backbone.js, Ember.js, ReactJS etc.
- Server-side technologies like Node.js, MongoDB, Express.js, etc.
- Solution Stacks like MEAN (MongoDB, Express.js, AngularJS)
Keep in mind that neither list is extensive. These are only meant as a starting point to help you get a feel for what you can expect and what keywords you can use to assess the best language for your needs.
Read more: Java vs. JavaScript: What’s the Difference?