Updated May 9, 2023
Introduction to AJAX Interview Questions and Answers
Most web technologies use AJAX, which stands for “Asynchronous JavaScript and XML,” as a set of web techniques or standards for developing web pages that offer rich user experiences and display content with less server loading. The data interchange format can be either XML or JSON, where JavaScript is native to JSON (JavaScript Object Notation); most modern web applications use JSON as the data format to interact with the database servers. AJAX includes a group of technologies, and people can use it with HTML, CSS, JavaScript, and various JS libraries.
The main of AJAX is to communicate with the server in the background by interrupting or reloading the existing web page by providing a rich user experience to the client or end-user of the application.
Below is the list of 2023 AJAX Interview Questions and Answers:
You have finally found your dream job in AJAX but are wondering how to crack the AJAX Interview and what could be the probable AJAX Interview Questions. Every interview is different, and the job scope is different too. Keeping this in mind, we have designed the most common 2023 AJAX Interview Questions and Answers to help you get success in your interview.
Part 1 – AJAX Interview Questions (Basic)
This first part covers basic interview questions and answers
1. What is AJAX, and explain it?
Answer:
AJAX (Asynchronous JavaScript and XML) refers to a group of technologies that enable the loading of page content in the background without disrupting or changing the current state of the web page.
The Document Object Model (DOM) API allows for the manipulation of the browser tree to provide dynamic functionality and dynamically change the content of a web page. The XMLHttpRequest object is used to achieve the asynchronous communication feature of AJAX. It is presented as an object and defined by WHATWG (Web Hypertext Application Technology Working Group), then later transferred to W3C (World Wide Web Consortium).
2. What are the different technologies used in AJAX?
Answer:
AJAX involves different technologies such as HTML (and XHTML), CSS (for the presentation layer), JSON, XML or XSLT (for data exchange between a web server and client), JavaScript, and other APIs for asynchronous communication. AJAX is used for creating dynamic web pages. Examples of AJAX websites are Google, Gmail, YouTube, Facebook, etc. AJAX is a standard based on Internet Standards to comply with all browsers and networks across the globe.
Let us move to the next AJAX interview question.
3. What is a synchronous request in AJAX?
Answer:
AJAX requests can be either synchronous or asynchronous, depending on the priority of the web server request. Careful configuration ensures the server responds to the user’s requirements. In synchronous requests, the script execution waits for the server’s response before proceeding to the next part of the script. This mechanism is crucial for a fast response, but frequent use can make the server less responsive. Therefore, it should only be used when the synchronous request mechanism is essential or unavoidable.
4. What is an asynchronous request in AJAX?
Answer:
An asynchronous request allows the script execution to proceed with the following line of execution regardless of the response from the web server after a request. The asynchronous is the most critical mechanism in providing the answers to the user without delay, where a user can still interact with the web pages irrespective of the responses from the Server for the previous requests.
5. What are the different ready states in AJAX?
Answer:
A ready state is a property in the XMLHttpRequest object which holds the status of the XMLHttpRequest.
The XMLHttpRequest undergoes different types of status changes that are available from 0 to 4.
0 – Request not initialized, 1 – Established connection with the server, 2 – Request received, 3 – Processing request, 4 – Request finished and a response is ready
When the status is 4, then the status can be described as HTTP status 200 (OK), which means the request is successful and the response is ready.
Part 2 – AJAX Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions.
1. What are the different stages and processes in AJAX-ready states?
Answer:
The different states and their processes are initialization, requesting, processing, and finishing in AJAX. When an open method is called on an object, the status changes to 1. When a send method is reached, the status changes to 2. After receiving the response from the Server, when a request ends, the situation changes to 4.
2. What is XMLHttpRequest Object?
Answer:
XMLHttpRequest (XHR) is a browser-level API (Application Programming Interface) that processes server-client requests using JavaScript. The XMLHttpRequest object is an API to establish communication between a server and the browser client.
Developers use XMLHttpRequest to update the page content without reloading the page and to request and receive data responses from the server even after the page has fully loaded request and receive the responses from the Server in the background without any interruptions to the user.
Let us move to the following AJAX Interview Questions.
3. What are the uses of XMLHttpRequest Object in AJAX?
Answer:
You can send an XMLHttpRequest based on the ready state change status. To create an XMLHttpRequest object, you can call the constructor new XMLHttpRequest ( ). XMLHttpRequest also handles Cross-Origin Resource Sharing (CORS).
4. What are AJAX applications in web development?
Answer:
The different applications of AJAX technologies include asynchronous calling, user-friendly, high-speed accessibility, etc. The real-time applications or websites currently using the AJAX are Google, Gmail, Google Maps, Amazon Inc., etc., where the content to the users is displayed without reloading the entire web page. The other applications include instant data validation, validating the forms on a web page before submitting, autocompletion of data in the fields based on the initially typed words, and refreshing dynamic data such as cricket scores, time, weather, loading of ads, stocks, etc.
Let us move to the following AJAX Interview Questions.
5. What are the real-time AJAX web applications?
Answer:
Real-time applications include various types of security authentications that developers can apply to AJAX web applications on both the server and client sides.
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