Chapter 20
Server Side Code
Server-side code refers to the code that runs on a web server rather than in a user's web browser. It is responsible for processing requests from clients (typically web browsers) and generating dynamic web pages or providing data to the client.
Client-side code refers to the code that runs in a user's web browser rather than on a web server. It is responsible for generating the user interface and handling user interactions. Client-side code is typically written in JavaScript and is executed by the browser.
Why do we need server-side code?
Server-side code is essential in web development for several reasons:
- Security: Server-side code is not visible to the user, so it is more secure than client-side code.
- Performance: Server-side code can be used to perform computationally expensive tasks, such as data processing, without affecting the user's experience.
- Data Storage: Server-side code can be used to store data in a database, which can then be accessed by the client-side code.
- User Authentication: Server-side code can be used to authenticate users and restrict access to certain parts of the website.
- Dynamic Content: Server-side code can be used to generate dynamic web pages, which can be customized for each user.
Server-side vs. Client-side
The differences are summarized in the table below:
| Server-side Code | Client-side Code |
|---|---|
| Runs on a web server | Runs in a web browser |
| Has access to server resources (file system, databases, etc.). | Has access to client resources (cookies, local storage, etc.). |
| Can be written in a variety of languages (PHP, Python, Ruby, Java, C#, etc.). | Can only be written in JavaScript. |
| May use server-side rendering (SSR) to generate HTML on the server. | Uses client-side rendering (CSR) to generate HTML in the browser. |
| Better for SEO as content is readily available for search engines. | Worse for SEO as content is not readily available for search engines. |
| Can leverage caching and Content Delivery Networks (CDNs) for performance. | Limited control over caching, relies on browser cache. |
Why use JavaScript for server-side code?
Unlike client-side code, which can only be written in JavaScript, server-side code can be written in a variety of languages, including PHP, Python, Ruby, Java, C#, and many more. So why use JavaScript for server-side code? There are several reasons:
Unified Language: Developers can use the same language and programming paradigms throughout the entire application stack, which can lead to code reusability and easier collaboration among front-end and back-end developers.
Large Ecosystem: JavaScript has a vast ecosystem of libraries and packages available through npm (Node Package Manager). This rich ecosystem simplifies the development process by providing pre-built modules for various functionalities, from server routing to database connectivity.
JSON: JavaScript Object Notation (JSON) is a popular data format that is used to transmit data between a server and a web application. JSON is based on JavaScript, so it is easy to work with JSON data in JavaScript.
Up next, we will learn how to use JavaScript for server-side code with Node.js and how to use Server Side Rendering (SSR) to generate HTML on the server.