jQuery Important Interview Questions

1. What is jQuery?
jQuery is not a programming language but a well written JavaScript code. It is a JavaScript code, which do document traversing, event handling, Ajax interactions and Animations.

2. Why jQuery is needed?
jQuery is needed for the following list:

• Used to develop browser compatible web applications
• Improve the performance of an application
• Very fast and extensible
• UI related functions are written in minimal lines of codes

3. Whether jQuery HTML work for both HTML and XML documents?
No, jQuery HTML only works for HTML documents not for XML Documents.

4. What are the methods used to provide effects?
Some of the effects methods are:

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

5. What is the advantage of using minimized version of jQuery?
Efficiency of web page increases when minimized version of jQuery is used.min.js file will be more than 50% less than the normal js file. Reduction in the file size makes the web page faster.

6. Is jQuery is a JavaScript or JSON library file?
jQuery is a library of JavaScript file and it consists of DOM, event effects and the Ajax functions. jQuery is said to be a single JavaScript file.

7. Which operating system is more compatible with jQuery?
Mac, Windows and Linux are more compatible with the jQuery.

8. How can we include jQuery library in ASP.Net project?
Download the jQuery library from jQuery.com and include that reference in the asp.net page.

9. Which command will give a version of jQuery?
The command $.ui.version returns jQuery UI version.

10. In what scenarios jQuery can be used?
jQuery can be used in following scenarios:

• Apply CSS static or dynamic
• Calling functions on events
• Manipulation purpose
• Mainly for Animation effects

11. What is the difference between find and children methods?
Find method is used to find all levels down the DOM tree but children find single level down the DOM tree.

12. What is jQuery connect?
A ‘ jQuery connect’  is a plugin used to connect or bind a function with another  function. Connect is used to execute function from any other function or plugin is executed.

13. How to use connect?
Connect can be used by downloading jQuery connect file from jQuery.com and then include that file in the HTML file. Use $.connect function to connect a function to another function.

14. What are the features of jQuery, has been used in web applications?
jQuery uses features like Sliding, File uploading and accordian in web applications.

15. What are the browser related issues for jQuery?
Browser compatibility of jQuery plugin is an issue and needs lot of time to fix it.

16. Whether we need to add jQuery file in both Master and Content page?
jQuery file should be added to the Master page and can use access from the content page directly without having any reference to it.

17. What are the basic selectors in jQuery?
Following are the basic selectors in jQuery:

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

18. Can we call C# code behind using jQuery?
Yes, we can call C# code from jQuery as it supports .net application.

19. What is the use jQuery.data method?
jQuery.data methods is used to associate the data with the DOM nodes and the objects. This data method makes the jQuery code clear and concise.

20. What is the use of each function in jQuery?
Each function is used to iterate each and every element of an object. It is used to loop DOM elements, arrays and the object properties.

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