jQuery Question and Answer Interview & Exam Preparation

1. What is jQuery?

Answer:
jQuery is a fast, lightweight, and feature-rich JavaScript library. It simplifies HTML document traversal, event handling, animation, and AJAX interactions for rapid web development.

2. Why do we use jQuery?

Answer:
We use jQuery to:

• Simplify JavaScript coding

• Handle events easily

• Perform animations

• Make AJAX requests

• Manipulate DOM elements

• Ensure cross-browser compatibility

3. What is the difference between JavaScript and jQuery?

Answer:

• JavaScript is a programming language.

• jQuery is a library built using JavaScript.

• jQuery makes JavaScript tasks easier and shorter.

Example:
JavaScript:

jQuery:

4. How to include jQuery in a website?

Answer:
You can include jQuery using a CDN link:

5. What is $(document).ready() function?

Answer:
It ensures that the code runs only after the HTML document is fully loaded.

6. What are jQuery Selectors?

Answer:
Selectors are used to select HTML elements.

Examples:

• $("#id") → Select by ID

• $(".class") → Select by class

• $("p") → Select all paragraphs

7. What is the use of .hide() and .show()?

Answer:
These methods hide and show elements.

8. What is jQuery AJAX?

Answer:
AJAX allows loading data from the server without refreshing the page.

9. What is the difference between .html() and .text()?

Answer:

• .html() sets or returns HTML content.

• .text() sets or returns only text content.

10. What is chaining in jQuery?

Answer:
Chaining allows multiple jQuery methods on the same element.

11. What are jQuery Events?

Answer:
Events are actions like:

• click()

• dblclick()

• mouseenter()

• mouseleave()

• keypress()

Example:

12. What is the use of addClass() and removeClass()?

Answer:

• addClass() adds CSS class

• removeClass() removes CSS class

13. What is the latest version of jQuery?

Answer:
The latest stable version (as of recent updates) is jQuery 3.x series.

14. What is the difference between == and === in jQuery/JavaScript?

Answer:

• == compares value only

• === compares value and data type

15. Is jQuery still used today?

Answer:
Yes, jQuery is still used in many websites, especially legacy projects. However, modern frameworks like React, Angular, and Vue are more popular for large applications.

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