June 16, 2019

Srikaanth

Gartner Most Frequently Asked JavaScript Interview Questions

Gartner Most Frequently Asked Latest JavaScript Interview Questions Answers

What is NaN in Javascript?

NaN is a short form of Not a Number. When a string or something else is being converted into a number and that cannot be done, then we get to see NaN. A strange thing about NaN is that it is not equal to anything including itself.

List out all the falsifying tokens in Javascript.

There are 6 tokens that falsify in Javascript and they are false, null, undefined, 0, NaN.

What is Currying in Javascript?

A partial invocation of a Javascript function is called Currying. Few arguments of a function are processed and a function is returned. Few more arguments are added by the returning function.

When do we use JSON.stringify()?

The JSON.stringify() method is used to convert a Javascript data to a string.

What does unshift() function do in Javascript?

Just like push() which inserts elements into an array at the end of it, the unshift() function inserts elements at the beginning of an array.

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

Whether jQuery HTML work for both HTML and XML documents?

No, jQuery HTML only works for HTML documents not for XML Documents.
Gartner Most Frequently Asked Latest JavaScript Interview Questions Answers
Gartner Most Frequently Asked Latest JavaScript Interview Questions Answers

What are the methods used to provide effects?

Some of the effects methods are:

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

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.

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.

Which operating system is more compatible with jQuery?

Mac, Windows and Linux are more compatible with the jQuery.

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.

Which command will give a version of jQuery?

The command $.ui.version returns jQuery UI version.

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

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.

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.

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.

What are the features of jQuery, has been used in web applications?

jQuery uses features like Sliding, File uploading and accordian in web applications.

What are the browser related issues for jQuery?

Browser compatibility of jQuery plugin is an issue and needs lot of time to fix it.

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.

What are the basic selectors in jQuery?

Following are the basic selectors in jQuery:

Element ID
CSS Name
Tag Name
DOM hierarchy

Can we call C# code behind using jQuery?

Yes, we can call C# code from jQuery as it supports .net application.

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.

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