Virtual DOM Vs. Browser DOM: Key Differences When Used In A React JS Framework


In front-end web development, React JS has, over time, emerged as one of the popular libraries in JavaScript. Its efficient rendering process plays a significant role in offering users responsive and smooth web applications. Now, the two major concepts that work to contribute to the rendering capabilities of React are Browser DOM and Virtual DOM.

Although the importance of both these are critical and essential for better fundamentals. But still, there are several speculations about the right usage of it over time and value. Let’s get a clear idea of both of these distinctions between virtual dom vs. browser dom performance and how it rightly impacts the performance of React. 

What is the DOM?

This is popularly known as the Document Object Model (DOM) and is a fundamental concept in the entire web development process. It mainly represents the structure and content of XML or HTML documents in a tree-like data structure. Each node on the tree-like data structure corresponds to a definite HTML element. Now, web development company developers usually use this actual JavaScript to interact rightly with the DOM and manipulate its elements and updates on the web page.

Understanding the Browser DOM

The Browser DOM is the live representation of the web page the user interacts with daily. When the browser loads an HTML document, it ultimately converts the entire data from HTML to CSS. This offers the resulting DOM tree to reflect the overall current state of the website pages rightly. If any changes are made to the DOM, it directly affects the displayed content, affecting the displayed content with repaint and reflow issues. 

The repaint and reflow impact an expensive overall set of operations as well. Now, while reflow offers the recalculation of the position of elements on the page, repaint helps to redraw the affected elements. If there are frequent changes to the entire use of browser DOM without hiring dedicated web developers, it can lead to performance bottlenecks in complex applications. 

What is Virtual DOM?

The Virtual DOM is a concept introduced by React JS to address the performance issues associated with directly manipulating the Browser DOM. Instead of making changes directly to the actual DOM, React creates a lightweight, virtual representation of it in memory. This virtual representation is essentially a JavaScript object that mirrors the structure of the Browser DOM but lacks the overhead of rendering and displaying elements on the screen.

Working on the Virtual DOM

When a React application is working, in case there are any definite changes to the overall application’s state, it can instantly trigger a reconciliation process. In most cases, React uses a relatively high diffing algorithm to compare the updated DOM with the virtual one effectively. This definite algorithm calculates the minimum number of changes to synchronize with Browser and Virtual DOM. 

The entire diffing process optimizes updates by identifying only the overall changed elements. Instead of updating the entire DOM tree, utilization of React can target specific nodes, minimizing the number of reflows and repaints required. Once the differences are calculated, React can efficiently apply these changes to the actual DOM, resulting in improved rendering performance.

Key Differences between Virtual DOM and Browser DOM

  • Performance:

One of the major reasons that facilitate React’s introduction of a Virtual DOM is to offer top-notch performance and value. Through this, the browser works by directly manipulating the overall Browser DOM. This can work by slowing down resource-intensive values and frequent updates. The Virtual DOM mitigates this issue by minimizing direct interactions with the Browser DOM and optimizing updates through the reconciliation process. This leads to offering a much more responsive and smoother website experience.

  • Reconciliation:

In the entire reconciliation process of React, Virtual DOM helps to calculate and offer essential changes to actual DOM ideally. This definite approach helps to reduce the overall number of updates on a significant website page that helps to reduce the affected parts of the webpage that have been repainted and reflowed. On the contrary, Browser DOM sometimes has a vague built-in mechanism to help developers perform manual checks and updates to identify performance challenges. 

  • In-memory Representation:

The Browser DOM is a live representation of the web page that consumes memory and processing power. The Virtual DOM, on the other hand, exists solely within the JavaScript environment and is an in-memory representation. By working with the Virtual DOM, React can perform all the necessary computations and optimizations when curated by a web development company. It is also a before applying the changes to the Browser DOM, leading to better memory management and performance.

  • Rendering Cycle:

A single change in a series can lead to excess time consumption in any application that directly manipulates Browser DOM. This can negatively affect the performance and reflow of the DOM structure. The Virtual DOM, however, batches updates and performs a single reflow and repaint process. This reduces the overall number of layouts by minimizing the overhead performance to a considerable level. 

  • Platform Independence:

Since the Virtual DOM is an abstraction part created by React, it is not tied to any specific browser or platform. This platform independence ensures consistent behavior across different browsers, making it effectively easy for developers to build cross-browser-compatible applications. In contrast, variations in browser implementations might lead to discrepancies in behavior and performance when working directly with the Browser DOM. Therefore, it is essential to research the virtual dom vs. real dom performance and utilize the best-fit option. 

  • Complex UI Interactions:

The Virtual DOM provides a significant advantage for applications with complex user interfaces. The diffing algorithm update also helps to avoid unnecessary recalculations by reducing the overall risk of bug introduction in the entire process. This makes it easier for front end web developers to manage and maintain large-scale applications with complex UI interactions.

When to Use Virtual DOM vs. Browser DOM

The decision to use the Virtual DOM or directly manipulate the Browser DOM depends on the complexity of the application and the performance requirements.

Use of effective Virtual DOM when:

  • When developing large-scale applications with complex UI interactions
  • Effective and improved performance is needed by minimizing direct manipulations on the Browser DOM.
  • Ensuring effective platform independence and consistent behavior across differentiated browsers.

Use Browser DOM when:

  • When building simple and static web pages with minimal interactivity
  • Dealing with small-scale applications where the performance gain from the Virtual DOM might not be significant
  • Working on projects where React’s performance optimization is not a critical concern overtime


In conclusion, the Virtual DOM and the Browser DOM are critical concepts in React JS development. The Virtual DOM introduces an abstraction layer that optimizes the rendering process, leading to improved performance and smoother user experiences.

By understanding the differences between the Virtual DOM and the Browser DOM, an informed and dedicated decision can be taken to leverage the full potential of React JS when building scalable applications from selected website development companies in the USA. Lastly, there is no doubt that React JS remains an invaluable tool in the modern web development landscape, enabling developers to build robust and user-friendly applications for a wide range of platforms and browsers.



Originally posted 2023-07-20 10:21:20.