Understanding Client-side Rendering and Server-side Rendering

Introduction

As a seasoned frontend engineer, you’ve likely traversed the expansive terrain of web development and encountered the enigmatic terms ‘client-side rendering’ (CSR) and ‘server-side rendering’ (SSR). Pause for a moment and ask yourself: ‘Can I confidently elucidate what CSR and SSR entail, and perhaps more importantly, distinguish the two?’

If your answer is a resounding ‘YES,’ then pat yourself on the back. You’re already on your way to mastering these concepts. However, if the answer leans toward the uncertain side, rest assured, you’re in the right place. Join us on a journey to demystify CSR and SSR, and emerge with a comprehensive understanding of their intricacies. But before we dive into these concepts, let’s take a step back and explore the fascinating evolution of front-end development.

The Evolution of Frontend Development

Frontend development has traversed an intriguing evolutionary path, significantly impacting how we render and interact with web content. To understand the current landscape of Client-Side Rendering (CSR) and Server-Side Rendering (SSR), it’s essential to revisit the origins of web rendering.

Server-Side Rendering (SSR): The Early Days

In the nascent days of the web, rendering primarily occurred on the server-side. Web servers were responsible for crafting fully-rendered HTML pages, which were sent to the browser for display. This server-centric rendering approach resulted in consistent page content but limited interactivity.

Client-Side Rendering (CSR): The Rise of Interactivity

The web’s evolution witnessed the rise of Client-Side Rendering (CSR) with the advent of JavaScript and AJAX. In CSR, the browser takes center stage, dynamically rendering content on the client-side. This shift brought about rich, interactive web applications.

A Return to Server-Side Rendering (SSR): Balancing Act

In recent years, frontend development has come full circle with a resurgence of Server-Side Rendering (SSR). The push for SSR arises from the need for better search engine optimization (SEO), improved initial page load times, and the ability to provide consistent content to users with varying devices and capabilities. Modern frameworks, such as Next.js and Nuxt.js, make SSR approachable.

Having examined the historical context and workflow behind Server-Side Rendering (SSR), Client-Side Rendering (CSR), and the resurgence of SSR, we are now well-prepared to dive deeper into each rendering method. In the following sections, we’ll explore the intricacies of both CSR and SSR. By the end of this exploration, you’ll have a comprehensive understanding of when and how to employ these techniques effectively in your web development projects.

Client-Side Rendering (CSR)

Client-side rendering, often synonymous with “single-page applications” (SPAs), fundamentally relies on rendering web content within the user’s browser. In CSR, the client’s web browser plays a central role in rendering content, offering a seamless and responsive user experience. To comprehend how CSR works, let’s break down the process step by step:

1. Initial Load: When a user accesses/requests a web page, the browser retrieves a minimal HTML page from the server, this initial HTML typically includes references to CSS styles and JavaScript files but lacks the main content.
2. Dynamic Content: Now once the initial HTML is loaded, JavaScript takes over. the javascript is often in the form of frontend frameworks or libraries, it sends requests to the server to fetch data necessary for the next step. These requests are commonly made through API calls.
3. Rendering: With the data in hand, JavaScript dynamically assembles the content on the client-side. This process involves manipulating the Document Object Model (DOM), which is a representation of the web page’s structure in the browser, the newly created content is then seamlessly displayed to the user, appearing as if it were there from the start. Let’s delve into the mechanics of CSR with illustrative code examples:

In the CSR example above:

• The process begins when a user accesses a web page that includes the index.html file. The browser initiates an HTTP request to the server to fetch this HTML file.
• The index.html file is a minimal HTML structure, including a section that specifies the page title and a section where the content will be displayed. Notably, it includes a
  element with the id attribute set to "app" and a reference to an external JavaScript file, "app.js," using a