Top 40 important jQuery questions for interview - All-time-dev

Basic jQuery interview questions

In this post, we will discuss the mostly asked jquery questions for an interview that an interviewer mostly asks and I will give both the questions and the answers you should reply to the interviewer after the question is asked. 

All the questions are fundamental and if you like reading or finding more interesting Java, JavaScript, and jQuery questions and answer for an interview like this, then don't forget to comment and share our posts with your friends we keep bringing more engaging content for you like you are reading now.

Table of Content

This is a small table of content and it is not clickable this is just to give you an idea of the overall content and some important questions related to it if you are interested to know the questions only.

• What is jQuery?
• Is jQuery a programming language and what is the use of jQuery?
• What is the basic difference between JavaScript and jQuery?
• Is jQuery the replacement for JavaScript?
• Why you should use jQuery?
• What is the use of the $() sign in jQuery?
• What are some jQuery functions used to provide effects?
• What is the use of the toggle() method in jQuery?

Find more by scrolling through the article ...

What is jQuery?

The most important question among all jQuery questions for an interview that has the maximum chance of being asked by the interviewer is what is jQuery? This simple answer is that jQuery is a fast, lightweight, and easy-to-use client-side JavaScript library that makes your JavaScript code shorter and easily understandable. 

It supports different types of browsers like Google Chrome, My favorite Mozilla Firefox, and more with cross-platform support, and in the past, years it increased the scope of JavaScript due to its short and simple syntaxes. 

When jQuery wasn't there then Javascript's code was lengthy and confusing, but now due to its support, a beginner can also use jQuery in the form of JavaScript. It helps you code logic and make your website interactive and faster more easily and in less time. 

What is the use of jQuery and is jQuery a programming language?

The short and simple answer to this is no, as I have told you earlier only that it is a well JavaScript-coded library. It is used for client-side website coding, for making interactive carousels, menus, and more. It is also used for animation and using APIs using AJAX (Asynchronous JavaScript and XML) and after this, I think you won't ask what is the use of jQuery at least now.

What is the basic difference between JavaScript and jQuery?

A fundamental difference between jQuery and JavaScript is that jQuery is a library coded in JavaScript to simply the JavaScript code while JavaScript is a programming language with the help of which jQuery is made up. 

Is jQuery the replacement for JavaScript?

No, jQuery is definitely not a replacement for JavaScript because it is made with JavaScript only and it is very different from JavaScript as it is a library. However, JavaScript has more new features in its new versions than jQuery which jQuery is trying to cover up. 

Why you should use jQuery?

There are major reasons why we should use jQuery and it gives a better answer to our question which we have discussed before what is the use of jQuery? The main reasons to use it are -

• It is advantageous to use, learn and understand.

• Has a short and simple syntax that helps you to develop sites faster.

• Its tutorials are easily available and its community is pretty which will help you if you face any issues while using it.

• It is used for developing websites for different browsers.

• It is fast and improves the speed of a site.

•  Supports cross-platform functionality.

• Good for SEO.

What is the use of the $() sign in jQuery?

The use of this $() is that it allows you to wrap into any jQuery object while coding which later helps you to make calls to the various method-defined jQuery objects. You can easily pass any selector string in the $() function and it returns a jQuery object as an array with all matched DOM elements.

What are some jQuery functions used to provide effects?

• Toggle()     
• Slide down()
• FadeOut()
• FadeToggle()
• FadeIn()
• Hide()
• Animate() and more.

What is the use of the toggle() method in jQuery?

The jQuery toggle method is a particular method that is used to toggle between the hide() and show() method. It hides and shows the elements to make the site interactive and logical like a nav bar that fades in and fades out the menu with lists like home, contact, testimonial, etc. There are also different parameters in the toggle() method like - 

speed - It specifies the speed of delay and its values can be milliseconds, slow and fast and this parameter is optional.

easing - It is used to specify the easing function for transition.

callback - like the first one it is also an optional parameter but it is also a very useful parameter it decides which parameter should be called after the toggle() is complete. 

display - if the display parameter is valid then it shows the element otherwise it hides the element.

What is the use of the fade toggle() method in jQuery?

This fade toggle() method is used to switch between the fade in() and fade out() method, for ex - if the elements are faded in() then it makes those elements fade out() and reverses the faded out() element as well.

speed - It determines the speed of delay and its values can be milliseconds, slow and fast and this parameter is optional.

easing - It is used to define the easing function for transition.

callback - Like the first one, it is also an optional parameter, but it is also a very useful parameter. It decides which parameter should be called after the toggle() is complete. 

display - if the display parameter is valid then it displays the element otherwise it hides the element.

What is the use of the delay() method in jQuery? 

The delay() method in jQuery hells you to make delay in execution of functions in a queue and it is also the best method used by developers to mark a delay between the jQuery effects like the fade toggle() etc. This method sets a timer to delay the execution of the next item or effect in the queue as I have discussed before. 

speed - It decides the rate of delay and its values can be milliseconds, sluggish and quick and this parameter is optional.

queueName - Like the first one, I told you it is also an optional parameter.  It is used to specify what is the name of the queue. And it's default value is "fx" Which is the standard queue effect. 

Can we use Apis and import content using jQuery? 

Yes, we can import data or content using jQuery with the help of jQuery AJAX (Asynchronous JavaScript and XML) from any site which provides its APIs for normal people, individuals, business owners, or agencies.

What is jQuery AJAX?

AJAX stands for Asynchronous JavaScript and XML, this is an amazing browser in-built XMLHttpRequest Object that always helps us to load content or data and exchange it with the servers across the globe without refreshing the browser page. jQuery is a very handy tool that provides us a lot of methods for our beloved AJAX to develop amazing web apps which we do with MERN now.

What is the use of the ajax() method in jQuery?

The ajax() method in jQuery sends an asynchronous XMLHttp request to the server to return some data.  

What is the use of the ajax method load()? 

This ajax method by jQuery is used to send an XMLHttp request to load the HTML of the webpage or the content from the server of the company or agency whose API we are using and adds that content to the Document object model element(s) at last as a result.   

What are the AJAX events in jQuery?

The jQuery library also adds jQuery AJAX events on their big library as a member that is fired in the future based on the AJAX request state, we call them AJAX events and there are two important jQuery event methods there that have very high chances of being asked by the interviewer during your interview they are - 

1. ajaxComplete()
2. ajaxStart()

What are events in jQuery?

The responses to the user actions on a web page are called events. jQuery provides us easy to handle and simple jQuery methods to affix event handlers to selections. When an event takes place by the click of the user or by visiting etc, the given function is executed.

What are the different categories in jQuery events?

The usual document object model events are as follows -

1. Keyboard.
2. Mice or Mouse.
3. Browser.
4. The loading document.
5. Form  

Can jQuery work for both XML and HTML documents?

The simple and short answer to this question is just no jQuery cannot work for XML documents it is made for HTML only and only works with HTML.

What is the use of jQuery connect and was it?

jQuery connect is a plugin from jQuery used to connect or attach a function with another one. It is used to start a function when any function from another object or plugin is executed.

Does Bootstrap use jQuery?

No, Bootstraps versions 4, 3, and the older versions used jQuery but in the latest update from Bootstrap on May 5, 2021, in version 5, jQuery is discarded and Bootstrap started using JavaScript instead of jQuery. However, now also we can use jQuery with Bootstrap.

What does jQuery used for client-side scripting or server-side scripting?

It is obvious that it is a JavaScript library and used as its replacement for the front-end. So, it is used for client-side scripting.

Does jQuery meet or is it a W3 standard?

No, jQuery isn't.

What are the basic requirements to start with jQuery?

You can easily start with jQuery with a basic laptop and to use jQuery either you can download the file and either you can link it with your HTML file or you can paste the CDN (only recommend if you have a good net) under the head section.

What is the beginning code if execution in jQuery?

$(document).ready(function(){}) is the code that you first have to write within script tags and you can start writing the syntaxes within the beginning code.

Can we use any other type of name instead of $ sign in jQuery?

Yes, we can write any other code instead of using the short-term dollar we can use the other term which is jQuery like jQuery(document).ready(function(){ ## here write the code}).

What is the use of the HTML() method in jQuery?

The jQuery HTML() method provides us the authority to just change the entire content of the elements which we have selected. It replaces the old content with the new content the best example is a responsive hamburger navigation bar.

Why do we use CSS() method in jQuery?

The jQuery CSS() method is simply used to get/return or to set style properties, and values, for some selected elements which we want to use for animation and to make the page more interactive. 

It provides us the authority to get one or more style properties using jQuery. The jQuery CSS() method provides two simple ways to do it either you can return a CSS property or you can simply just set a specific value.

What is the basic difference between find and child methods in jQuery?

The most basic and important difference between them is that the find method is used to search all the levels below the DOM (Document Object Model) tree which has numerous branches. In contrast, the child method is just used to find or search a single level below the branched document object model tree.

What is the meaning of a CDN?

A CDN is a content distribution network or you can also say content delivery network which enables us the files from servers of different agencies or companies whose CDN we are using at a greater bandwidth which makes the loading time faster. 

It is a largely spread system of servers posted in numerous data centers across the World Wide Web or you can say the internet in the entire globe. Many companies provide public CDNs for free of cost but the popular ones are -

1. Google. 
2. Microsoft (My favorite).
3. Facebook.

What is the purpose of using a CDN?

The final and main purpose of a CDN is just to provide the content to the user with high performance and availability to the end-user who wants to use it for their tasks, projects, etc. The best example of providing high-quality CDN is Bootstrap, jQuery, and Cloudflare.

What are the advantages of using a CDN?

The most important and notable advantages of a CDN are as follows-

1. It increases the speed of a website and decreases the load of content on the server.
2. It saves a lot of bandwidth. jQuery library loads faster with the help of these CDNs which increased the speed and rankings of websites on the SERPs.
3. If someone regularly visits our site who is using the jQuery library from Google, Microsoft, or from anyone CDNs then, that will be cached. 

What is the use of a jQuery filter?

The jQuery filter is used for filtering the specific values from the objects. jQuery filter simply filters the results of your initial query into fixed or particular elements. 

What are selectors in jQuery? 

If you are a web developer and you are working with jQuery on your webpage, the first thing you need to do is to search it. Jquery Selectors helps you to search the HTML elements in jQuery.

How many different types of selectors does jQuery consist of?

There are mainly three types of selectors that jQuery consists they are -

1. CSS selector
2. XPath selector
3. Custom selector

How many types of selectors does it consist of?

If you are confused between the three selectors I discussed and now, this selector then simply, the selectors that I have discussed above are the main types of selectors and the selectors which I am discussing now, are the selectors which come under these three selectors. There are many types of sectors but we will discuss some of the basics they are -

1. ID - It is just used to choose a single type of element that matches the id you have provided.
2. Name - It is just used to select or choose all the elements that caught to be similar to the provided element's name.
3. .Class - This selector is simply used to choose all the elements that match the specified class.
4. Universal (*) -  Universal selector is used to choose all the elements available to the Document Object model. 
5. Attribute selector - The Attribute selector has used chosen elements based on their attribute value.
6. Multiple Elements E, F, and G - They are used to choose the combined outcome of all the given selectors E, F or you can also use G.

What is the basic difference between the ID and even class selector in jQuery?

As we already know the concept of ID selector and Class selector in CSS, as it is are same in jQuery also. The ID selector uses the ID to select the elements while classes are used for selecting classes like in CSS. 

You can even utilize an ID selector to use only one type of element or only one element in an HTML file and if you want to choose or select a bunch of elements, having the same class used in CSS then you should use a class selector this is the most important and basic difference between them.

Conclusion 

The list I have provided has the highest chance of being asked and this will be a good preparation syllabus for your jQuery interviews in 2022 this is also relevant for the next 5 years. So, in today's post, I have given you both the jQuery questions and answers for interview the only thing that you should do now is to practice for your interview and be confident.