Best 20 Questions for jQuery : Most asked Interview Questions for Freshers

Best 20 Questions for jQuery : jQuery is a JavaScript library that simplifies HTML DOM manipulation, CSS style, and event handling. It’s a popular choice among web developers because of its succinct syntax and ability to automate basic activities. jQuery provides a more consistent and efficient way to interact with web pages than raw JavaScript, allowing for cleaner and more maintainable code.

A jQuery developer is a web developer that specializes in using the jQuery library to build dynamic and interactive online applications. They have a solid understanding of JavaScript, HTML, the jQuery API, and its many plugins. jQuery developers frequently work on projects that involve advanced DOM manipulation, AJAX calls, or bespoke animations. Their talents are useful in developing modern web applications that offer a great user experience.

here are Best 20 Questions for jQuery : Most asked Interview Questions for Freshers

1. What is JQuery Used For?

In web development, jQuery is most commonly used to simplify HTML DOM manipulation, CSS styling, and event handling. It offers a more concise and effective approach to interact with web pages than raw JavaScript. By encapsulating typical DOM activities in a more intuitive syntax, jQuery minimizes the amount of code needed to do certain tasks.

2. Why is jQuery known as a feature-rich library?

jQuery’s reputation as a feature-rich library originates from its broad set of built-in functions and methods for simplifying basic web development chores. Aside from its core functionalities of DOM manipulation, CSS style, and event handling, jQuery has a plethora of features that make it a useful tool for web developers.

3.What is the purpose of jQuery AJAX?

AJAX (Asynchronous JavaScript and XML) is a powerful technique that allows web applications to communicate with remote services without requiring a complete page refresh. This means that data can be loaded, updated, or retrieved from a server while the user experience remains uninterrupted.

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4. Does Bootstrap require jQuery?

Bootstrap used to rely heavily on jQuery to provide JavaScript capabilities. Many of its components and plugins were written with jQuery, giving developers a uniform and familiar API. However, Bootstrap 5 made major modifications to lessen its reliance on jQuery.

While jQuery is no longer a required for Bootstrap 5, it is still recommended in some situations. If you use earlier jQuery-based plugins or custom scripts that rely on jQuery, you must include it in your project. Furthermore, some Bootstrap components, such as tooltips and popovers, may require jQuery for specific capabilities or customizations.

Overall, the option to employ jQuery with Bootstrap 5 is based on your individual requirements and tastes. If you are starting a new project and do not have any current jQuery dependencies, you can utilize Bootstrap 5 without them. However, if you’re working with legacy code or need to keep older plugins operating, you may need to include jQuery.

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5.Explain $(document).ready() function?

When you use the $(document).ready() function, you’re telling jQuery to wait until the DOM is ready before running your JavaScript code. This eliminates problems and ensures that your JavaScript can interact with HTML components properly. For example, if you want to add an event listener to a button, you should include the code within $(document).ready() to ensure that the button exists before the listener is added.x

The $(document).ready() function in jQuery is an important tool for ensuring that your JavaScript code runs only after the HTML document has been fully loaded. This is crucial because JavaScript cannot manipulate components that have not yet been parsed and added to the Document Object Model (DOM).

When you use the $(document).ready() function, you’re telling jQuery to wait until the DOM is ready before running your JavaScript code. This eliminates problems and ensures that your JavaScript can interact with HTML components properly. For example, if you want to add an event listener to a button, you should include the code within $(document).ready() to ensure that the button exists before the listener is added.

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6.What is jQuery Mobile?

jQuery Mobile is a complete HTML5 framework that creates a consistent user interface across devices and platforms. It makes it easier to create mobile-friendly websites and applications by providing a wide range of pre-designed components and functionalities.

One of jQuery Mobile’s main advantages is its ability to adapt to different screen sizes and orientations. It employs responsive design concepts to ensure that your website looks and performs properly on a variety of devices, ranging from smartphones and tablets to PCs. Furthermore, jQuery Mobile includes a diverse set of UI elements, like as buttons, sliders, grids, and forms, making it simple to create visually beautiful and dynamic interfaces.

7.What are events in jQuery?

Events in jQuery are activities or occurrences that take place on a web page or application. They can be triggered by user behaviors like clicking a button or inputting text, as well as system events like page loading or window resizing. jQuery offers a robust and adaptable method for handling events and responding to them in a dynamic and interactive way.

Events in jQuery are activities or events that happen on a web page or application. They can be triggered by both user actions, such as pressing a button or entering text, and system events, such as page loading or window resizing. jQuery provides a powerful and customizable approach for managing events and responding to them in a dynamic and interactive manner.

8.What is jQuery click event?

When a user clicks on an element in jQuery, the click event is triggered. It is one of the most often used events in web development, allowing you to do actions in response to user input.

9.Can you explain about ajaxStart() functions?

The ajaxStart() function in jQuery allows you to execute a specific piece of code whenever an AJAX request begins. This is handy for presenting visual feedback, such as a loading spinner, or limiting user input while a request is being processed.

When an AJAX request is made, jQuery determines if there are any outstanding requests. If this is the first request, the ajaxStart() event is raised, and any registered handlers are executed.

10.What is CDN?

A CDN (Content Delivery Network) is a distributed network of servers strategically situated throughout the world. It is intended to deliver material to users as quickly and efficiently as possible, regardless of their geographical location.

A CDN (Content Delivery Network) is a distributed network of servers spread around the world. It is designed to deliver content to users as rapidly and efficiently as possible, regardless of their physical location.

11.Explain jQuery no-conflict.

The jQuery no-conflict mode is a feature that allows you to use jQuery alongside other libraries that also utilize the $ symbol. This is especially important when working with several JavaScript libraries that may conflict if they share the same $ symbol.

By enabling no-conflict mode, you can give the jQuery object an alternative variable name. This way, you may avoid naming conflicts and seamlessly integrate jQuery and other libraries into your project.

12.What is the goal of CDN and what are the advantages of using CDN?

A material Delivery Network (CDN)’s primary purpose is to deliver material to users as quickly and effectively as possible, regardless of geographical location. CDNs increase website performance by distributing material across a global network of servers.

advantages of using CDN

• It minimizes the server’s load.
• It saves bandwidth. The jQuery framework loads quicker from these CDNs.
• If a visitor often visits a site that uses the jQuery framework from one of these CDNs, it will be cached.

13.Explain the concept of method overriding in jQuery plugins.

Method overriding in jQuery plugins allows you to change the behavior of existing plugin methods without directly modifying the plugin’s source code. This gives a versatile and maintainable way to tailor the functionality of plugins to your own requirements.

When you create a jQuery plugin, you specify which methods can be invoked on plugin instances. Using method overriding, you can build a new plugin instance and redefine any of its methods to execute other functions. This enables you to expand the plugin’s functionality, add new features, or modify its behavior without changing the original plugin code. This technique encourages code reuse and makes it easier to maintain and upgrade plugins over time.

14.How does event delegation work in jQuery?

In jQuery, event delegation is a technique in which event handlers are attached to a parent element rather than the child components. This can considerably boost performance, particularly when dealing with a high number of dynamic elements.

When an event happens on a child element, it propagates up through the parent elements until it reaches the element to which the event handler is attached. If the event meets the handler’s criteria, the handler is run. This allows you to handle events for numerous child elements with a single event handler on their parent, which reduces the number of event handlers required and improves speed.

Event delegation is especially handy when working with dynamically created parts. Instead of adding event handlers to each element when it is formed, connect a single event handler to the parent element and utilize event delegation to handle events for all child elements. This can make your code simpler and more efficient.

15.What is jquery.min.js?

jQuery.min.js is a reduced version of the jQuery JavaScript library. Minification is the process of removing extraneous characters from code, such as whitespace, comments, and formatting, in order to minimize the file size. This lower file size can enhance website performance by reducing the time required to download and execute JavaScript code.

Using the minified version of jQuery is generally recommended for production websites because it can aid with load times and overall performance. However, it is critical to utilize the unminified version for development because it is easier to read and debug. The jQuery website normally contains both minified and unminified versions of jQuery.

16.What is a content distribution network?

A material Delivery Network (CDN) is a geographically distributed network of computers that aims to deliver material to users as quickly and efficiently as feasible. It works by storing static material (such as photos, CSS files, and JavaScript) closer to the user’s location, minimizing the distance data must travel and improving load speeds.

When a user requests a web page, the CDN determines whether it has a cached version of the requested content. If accessible, it sends the content straight to the user, bypassing the website’s original server. This greatly minimizes latency, resulting in faster website performance and a better user experience. CDNs are critical for websites that have a worldwide audience or experience significant traffic levels.

17.Differentiate between onload() and document.ready().

onload() is a JavaScript event handler that is called when the entire page, including all resources such as pictures, scripts, and stylesheets, has finished loading. It’s a more general-purpose event that ensures your JavaScript code runs only once the page is fully loaded.

Document.ready(), on the other hand, is a jQuery-specific function that is called as soon as the HTML DOM (Document Object Model) loads. This implies that it executes your JavaScript code as soon as the HTML structure is complete, rather than waiting for additional resources to finish loading. This is frequently preferred because it allows you to alter DOM components directly, which improves perceived performance.

18.What exactly is a jQuery Data Table plugin? 

A jQuery Data Table plugin is a JavaScript library that extends the features of HTML tables. It enhances simple tables with interactive capabilities such as sorting, filtering, and paging, transforming them into dynamic and user-friendly data presentation components.

By using a Data Table plugin, you can give your users a more easy and efficient way to work with massive datasets. Users, for example, can simply sort columns to arrange data in the desired order, filter results based on specific criteria, and utilize pagination to explore big tables. These features improve the overall user experience by making it easier to locate and analyze the information you require.

19.Explain what the dollar sign does in jQuery.

The dollar sign ($) in jQuery represents the jQuery object. It’s a quick way to use jQuery’s functions and methods without having to input the complete jQuery object every time.

When you use the dollar sign followed by a selector, you are effectively constructing a jQuery object that represents the selected components. For example, $(‘p’) picks all paragraph elements on the page and produces a jQuery object with those components. You can then use jQuery’s methods to edit these elements’ attributes, styles, or event handlers.

20.Explain what CSS() does in jQuery.

The css() method in jQuery is used to change the CSS properties of selected components. It can be used to obtain and set CSS values. To obtain the value of a CSS property for a specific element, send the property name as an argument to the css() method.

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