JQuery interview Questions and answers for Fresher & Experienced

Introduction

JQuery is a client-side scripting language and this is based on HTML DOM or Document Object Model that is designed to simplify the HTML and CSS scripting. A number of companies are adopting JQuery for their organizational applications and therefore the requirement for JQuery professionals is also increasing in the market. If you are also planning to start your career in IT then JQuery is just the best option for you.

In this blog, we are going to discuss JQuery and commonly asked interview questions for this profile. As it is one of the most in-demand scripting languages, so we have collected all of the relevant and common questions that are usually asked by the interviewers to JQuery professionals:

JQuery interview Questions And Answers

1. What is JQuery, describe in brief.
2. What is the requirement of JQuery?
3. Do JQuery syntax is same of both XML and HTML?
4. List the JQuery methods that are used to provide effects.
5. What is the significance of $() in JQuery explain it?
6. Enlist or tell some of the JQuery advantages.
7. Differentiate between the class selector and ID selector in JQuery.
8. What is the difference between this and $() this keyword in jQuery?
9. Why is jQuery library usually loaded by using CDN?
10. Define ID and class in jQuery
11. In JQuery what do you understand by grouping?
12. What is HTML and Semantic HTML?
13. Is jQuery a JSON or JavaScript library file?
14. Which operating system is compatible with JQuery?
15. Where can we use JQuery?
16. What is JQuery connecting and how we can use it?
17. Is there any issue with browsers in jQuery?
18. Enlist JQuery basic selectors?
19. Explain the difference between length and size of JQuery.
20. Enlist four JQuery Ajax method parameters.
21. What is CDN, explain its types?
22. How can a JQuery be debugged?

JQuery interview questions and Answers for Fresher

Q1). What is JQuery, describe in brief.

JQuery is a scripting language and is not a programming language or we can say that it is a well-written JavaScript code. This JavaScript code can perform Ajax interactions, event handling, and Animations.

Q2). What is the requirement of JQuery?

However, JavaScript was already being used by the programmers as a scripting language but JQuery has become one of the favorites of programmers due to following reasons:

• The user can develop browser compatible web applications easily through JQuery
• It can improve web application performance
• It is an extensible and fast language
• The user can write UI related functions just in few lines 

Q3). Do JQuery syntax is same of both XML and HTML?

JQuery is compatible only with HTML documents and cannot work with XML documents.

Q4). List the JQuery methods that are used to provide effects.

Following listed methods can provide effects:

• Show ()
• Toggle ()
• Hide ()
• FadeIn ()
• FadeOut ()

Q5). What is the significance of $() in JQuery explain it?

In JQuery we can use $() at the place of jQuery () function so it is an alias of jQuery () function. Initially, you may feel it not suitable and appropriate but when you will become familiar with this function then you will surely love it. Any object can be wrapped under $() function, it can then be used to call the functions that are defined through jQuery object. A selector string can also be passed to $() function that will return of an array of all of the matching DOM elements of JQuery.

Q6). Enlist or tell some of the JQuery advantages.

JQuery offers following advantages over other scripting languages that are:

• AJAX Capability
• Cross Browser support
• Easily expandable
• Easy to learn and use
• Event handling and detection
• Tons of plugins for all types of needs
• A number of built-in methods
• Easy traversal and DOM manipulation methods

Q7). Differentiate between the class selector and ID selector in JQuery.

The difference may be clear to the XML users and the same difference is there in JQuery as well between both. The elements can be selected by ID selector that uses element ID to select them like #element1 and to select only one element you can use ID selector.

To select a group of elements from same CSS class you can use a class selector. If you are being asked to tell the difference between syntax of ID selector and class selector then the difference is that ID selector use ‘#’ while class selector use “.” character.

Q8). What is the difference between this and $() this keyword in jQuery?

If you are a beginner then this question may be somewhat trickier for you, but otherwise, it is not a difficult one. $(this returns a jQuery object for which several jQuery methods can be called like eval () to call value, text () to retrieve text.

On the other hand, this keyword represents the current object and this JavaScript keyword is used to represent current DOM element. Any jQuery method cannot be called on this, for that it must be wrapped by using $() function.

Q9). Why is jQuery library usually loaded by using CDN?

For JQuery beginners, it can be slightly advance question, but usually, the jQuery library is loaded by CDN because It is quite faster to download and in case if the browser has already downloaded the same jquery then it will not be downloaded again. Today most of the websites use JQuery for animation and user interaction, so your browser may have already downloaded jQuery.

Q10). Define ID and class in jQuery

In jQuery class is a style or group of CSS attributes and can be applied to one or more HTML elements. In other words, it can be applied to the instance of same or different objects to which the same style is attached. JQuery classes are defined by periods that is followed by the class name. Usually with the help of class name and class attributes it is applied to an HTML element.

ID selectors are applied to a specific style of JQuery. It can be associated with one HTML element with an assigned ID. The ID selectors are defined by # in CSS that is followed by the selector name.

Q11). In JQuery what do you understand by grouping?

When the same declaration is used by more than one selectors then they can be grouped together and are separated by a comma. In this way, CSS size can be reduced (As in programming every byte and bit is important) and can be made readable.

Q12). What is HTML and Semantic HTML?

HTML stands for Hyper Text Mark-up Language that is a language of World Wide Web. This is a language of standard text formatting that is used to design a web page. HTML web pages are designed with the help of two things one is content and other is a tag, that is used for proper page display.

Semantic HTML is not much different but is just a style of coding and in that tags embody what text is meant to convey. In semantic HTML some of the syntaxes for tags may be different than usual HTML syntaxes.

Q13). Is jQuery a JSON or JavaScript library file?

JQuery is a library file of JavaScript and consist of DOM event effects and AJAX functions. JQuery is just a single file of JavaScript file.

Q14). Which operating system is compatible with JQuery?

Windows, Linux and Mac operating systems are more compatible with JQuery.

Q15). Where can we use JQuery?

We can use JQuery in following scenarios:

• To call functions or events
• For manipulation purpose
• For animation effect
• Apply dynamic and static CSS

JQuery interview questions and Answers for experienced

The following questions are asked of the experienced candidates of JQuery professionals:

Q16). What is JQuery connecting and how we can use it?

If we want to connect one or more functions with each other then for that purpose JQuery connect plugin is used. If we want to execute one function from another function then we can use Connect plugin.

We can use the Connect plugin by downloading the JQuery connect file from jQuery.com and then we can include it in the HTML file. The $. Connect function can be used to connect two or more functions.

Q17). Is there any issue with browsers in jQuery?

The big issue with the JQuery browser is compatibility which may need a lot of time to fix.

Q18). Enlist JQuery basic selectors.

The basic JQuery selectors are listed below:

• CSS Name
• Element ID
• Tag Name
• DOM hierarchy

Q19). Explain the difference between the length and size of JQuery.

By length and size, we can get the total number of elements of the JQuery object. They are usually used to loop arrays, object properties, and DOM elements.

Q20). Enlist four JQuery Ajax method parameters.

The four parameters that are used with JQuery Ajax methods are:

• Type: It is used to specifically request type that can be get or post
• URL: Is used to specify the URL to which the request is being sent
• Data: Is used to send data to the server
• Cache: Is used to know whether the requested page can be cached or not.

Q21). What is CDN, explain its types.

The content distribution network is known as CDN. A group of companies from different locations and networks contains the data file copies that are used to maximize the bandwidth so that data can be easily accessed. The following two types of CDN can be used by programmers:

• Microsoft: It loads JQuery from Ajax CDN
• Google: It loads libraries of JQuery from Google library API

Q22). How can a JQuery be debugged?

The following two ways are used for debugging in JQuery:

• We can attach breakpoints after attaching the process
• We can add a debugger to the line from where we want to start debugging and then by running Visual Studio in Debug mode we can debug the code.

Conclusion

In this way, we can see that the number of questions that are asked by the interviewer in JQuery interviews can be of many types and the difficulty level will depend on your experience level.