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Best Interview Questions in jQuery for Starters

We have some questions you may expect during the jQuery interview if you have received a call for an interview for the role of jQuery coder. Users are required to be familiar with JavaScript as it is one of the essential requirements.

Best Interview Questions in jQuery for Starters

Below are some of the questions that may be asked to a jQuery coder in an interview:

1. Define jQuery.


jQuery is a quick, lightweight, feature-rich client-side JavaScript library. It is cross-platform and promotes several types of browsers. It has contributed to JavaScript’s required boost as before jQuery the course of JavaScript small and the and bigger even for smaller functions. It advances a website and makes it more interactive and attractive.

2. Is jQuery an app programming language?


jQuery is a very well written JavaScript code and it can be used for traversing documents, event handling, ajax interaction and animation.

3. What is the difference between JavaScript and jQuery?


The simple difference between JavaScript and jQuery is that JavaScript is a language, whereas jQuery is a built-in library developed for JavaScript. The use of JavaScript language is specified by jQuery.

4. Is jQuery a replacement for JavaScript?


jQuery is not a replacement for JavaScript. It is written on top of JavaScript, and it has a distinct library. jQuery is a lightweight JavaScript library used for combining JavaScript and HTML.

5. Why do we use jQuery?


  • jQuery is easy to learn and use.
  • It is used for developing browser compatible web applications.
  • It enhances the execution of an application.
  • It is very fast and extensible.
  • It helps us in writing minimal lines of code for UI related functions.
  • Cross-browser support is also provided by jQuery.

6. What is the use of $() in the jQuery library?


The $() function is an pseudonym of of the jQuery ()function. It is used to wrap any object into a jQuery object that later helps you call the various method defined jQuery object. A selector string could either be passed to $() function, and IT returns a jQuery object that comprises an array of all matched DOM elements.


$(document).ready(function() {  
$("p").css("background-color", "pink");  

7. What are the effects methods applied in jQuery?


Below are some effects methods utilized in jQuery:

  • show(): used for displaying or showing the selected elements.
  • Hide (): used for hiding the matched or selected elements.
  • toggle(): used for showing or hiding the matched elements. It also toggles between the hide() and shows() methods.
  • fadeIn(): used for showing the matched elements by decreasing it to opaque. In other words, it fades in the selected elements.
  • fadeOut(): used for showing the matched elements by feeding it transparent. It could also be understood as it fades out the selected elements.

8. Explain the usage of the toggle() method in jQuery?


The jQuery toggle() is a specific type of procedure used for toggling between the hide() and show() method. The hidden elements are shown, and shown elements are hidden by it.


$(selector).toggle(speed, callback);  
$(selector).toggle(speed, easing, callback);  

Speed: It is an optional parameter as it specifies the speed of delay. Slow, fast, and milliseconds are possible values.

Easing: It is used for specifying the easing function to be used for transition.

Callback: It is also an optional parameter as it specifies the function to be called after the achievement of the toggle() effect.

Display: If true, then it displays an element, and if false, it hides the element.

9. What is the use of the fadeToggle() method in jQuery?


We use the fadeToggle() method in jQuery for toggling between the fadeIn() and fadeOut() methods. It makes the elements fit in if they are faded out.


$(selector).fadeToggle(speed, easing, callback);  

Speed: The speed of delay is not required as it is an optional parameter. Its possible values are fast and milliseconds.

Easing: This function can be used for specifying the transition.

Callback: Callback specifies the function that we will be calling after the completion of the fadeToggle() effect.

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


The delay()method in jQuery is used for delaying the execution of functions in a queue. It is the best method for making a delay between queued jQuery effects. The delay() method in jQuery sets a timer for delaying the next item execution in the queue.


$(selector).delay (speed, queueName)    

Speed: It is an optional parameter, and it defines the speed of the delay. Slow, fast, and many seconds are the possible values.

QueueName: It is also one of the optional parameters, and it designates the name of the queue.

11. What is the use of html() method in jQuery?


The html() method in jQuery is used for changing the complete content of the elements selected. It is used for replacing the selected element content with new content.


        $("p").html("Hello <b></b>");    

12. Explain the differences between width() and css(‘width’) in jQuery.


The width value is returned in pixels by CSS(‘width’) whereas in width() IT returns integer without any unit values.

For example:

width: 20cm;
If you print the values:

You will obtain values like 756 and 756px. Note that even though we’re specified the width in centimeters, it will be converted into pixels for output purposes.

13. State the differences between bind(), live() and delegate() methods in jQuery.


bind(): The event handler is directly registered into the required DOM element by this method.

Eg: $(“#members a”).bind(“click”, function(f){….});

It indicates that matching anchors will be having this event handler attached.

live(): The root of the document is attached to the event handler by this method. It is an indication that we can use one hand for handling all events delivered to the root. Hence one handler is attached only once.

delegate(): We can choose if we want to attach the handler in this method as it is one of the most efficient and robust methods for delegation.

Eg: $(“#members”).delegate(“ul li a”, “click”, function(f){….});

14. What is the use of the param() method in jQuery?

It serializes the representation of an object or array is displayed as an output by the param() method.

For example:

student = new Object(); = “Mary”;
student.marks = 67;

The method will give the following output when an event occurs that calls this code




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