XMLHttpRequest vs WebSocket: Which One to Choose?

When it comes to web development, there are a lot of tools and technologies that you can use to create amazing applications. Two of the most popular ones are XMLHttpRequest and WebSocket. While they might sound similar, they have different use cases and functionalities. In this article, we’ll explore the differences between XMLHttpRequest and WebSocket, and when you should use one or the other.

What is XMLHttpRequest?

XMLHttpRequest, also known as XHR, is a JavaScript API that allows you to send HTTP requests and receive responses from a web server. It was originally designed by Microsoft for Internet Explorer, but it’s now supported by all major browsers. With XHR, you can make asynchronous requests, which means that you can send a request to the server without blocking the user interface. This makes it great for fetching data and updating parts of a web page without having to reload it entirely.

XHR can be used for a variety of tasks, such as:

1. Fetching data from a server
2. Submitting form data
3. Updating parts of a web page
4. Verifying user credentials

When you make an XHR request, you can specify the HTTP method (GET, POST, PUT, DELETE, etc.), the URL of the server, and any parameters or headers that you want to send along with the request. Once the request is sent, you can handle the response in different ways, such as displaying the data on the page or using it to update the state of your application.

What is WebSocket?

WebSocket is a protocol that enables real-time, bidirectional communication between a web browser and a server. It was standardized by the IETF in 2011 and is now supported by all major browsers. Unlike XHR, WebSocket allows you to keep a permanent connection between the client and the server, which means that you can send and receive data instantly without having to make a new request every time.

WebSocket is great for applications that require real-time updates, such as chat rooms, online gaming, and stock market tickers. With WebSocket, you can send messages back and forth between the client and the server in real-time, without having to worry about latency or network congestion.

XMLHttpRequest vs WebSocket: What’s the Difference?

Now that we know what XHR and WebSocket are, let’s compare them and see how they differ:

1. Request-Response Model

XHR follows a request-response model, which means that the client sends a request to the server and waits for a response before taking any further action. This can result in latency and slow performance, especially if the server takes a while to respond or if there’s a lot of network traffic.

WebSocket, on the other hand, uses a persistent connection that allows data to be sent and received in real-time, without having to wait for a response. This makes it more efficient for applications that require real-time updates or instant messaging.

2. Compatibility

XHR is supported by all major browsers, including Internet Explorer 6 and above. It’s also widely used in web development and has a large community of developers who contribute to its development and improvement.

WebSocket, on the other hand, is a relatively new technology and is not supported by older browsers, such as Internet Explorer 9 and below. This means that if you want to use WebSocket, you’ll need to make sure that your target audience is using modern browsers that support it.

3. Security

XHR can be vulnerable to cross-site scripting (XSS) attacks, which can allow malicious actors to steal sensitive information from your users. To prevent this, you need to make sure that your server is properly configured and that you’re using HTTPS to encrypt your data.

WebSocket, on the other hand, has built-in security features that prevent XSS attacks and other types of vulnerabilities. WebSocket uses the same origin policy, which ensures that data can only be sent and received between the client and the server that originated it. This makes it more secure than XHR for real-time applications.

4. Data Format

XHR can send and receive data in different formats, such as JSON, XML, and plain text. This makes it flexible and easy to use with different types of data.

WebSocket, on the other hand, can only send and receive data in binary or text format. This means that if you want to use WebSocket with JSON or XML data, you’ll need to encode and decode it manually.

5. Server Overhead

XHR requires a new connection to be established every time a request is made, which can put a strain on the server and increase its overhead. This can be especially problematic for high-traffic applications that require frequent requests.

WebSocket, on the other hand, uses a persistent connection that reduces the server overhead and allows for more efficient communication between the client and the server.

When Should You Use XHR?

XHR is a great choice for applications that require fetching data from a server or updating parts of a web page without having to reload it entirely. Here are some examples of when you might want to use XHR:

• Fetching user data from a server
• Submitting form data
• Updating a shopping cart
• Updating a news feed

When Should You Use WebSocket?

WebSocket is a great choice for applications that require real-time updates or bidirectional communication between the client and the server. Here are some examples of when you might want to use WebSocket:

• Real-time chat rooms
• Multiplayer online games
• Stock market tickers
• Real-time dashboards

FAQ

1. Can I use XHR and WebSocket together?

Yes, you can use XHR and WebSocket together in the same application. In fact, they complement each other and can be used for different parts of the same application. For example, you might use XHR to fetch data from a server and then use WebSocket to update it in real-time.

2. Which one is faster, XHR or WebSocket?

WebSocket is generally faster than XHR because it uses a persistent connection that allows data to be sent and received in real-time, without having to wait for a response. However, the actual performance depends on the specific use case and the amount of data being sent and received.

3. Is WebSocket more secure than XHR?

WebSocket has built-in security features that prevent XSS attacks and other types of vulnerabilities. However, XHR can also be made secure by properly configuring your server and using HTTPS to encrypt your data.

4. Which one should I choose, XHR or WebSocket?

The choice between XHR and WebSocket depends on your specific use case and the requirements of your application. If you need real-time updates or bidirectional communication, WebSocket is the better choice. If you need to fetch data from a server or update parts of a web page without reloading it, XHR is the better choice.

Conclusion

XHR and WebSocket are both powerful tools that can be used to create amazing web applications. Understanding the differences between them and when to use each one can help you create more efficient and effective applications. Whether you choose XHR or WebSocket, make sure to use them properly and securely to ensure the best possible user experience.