11 Complex Questions Asked in JavaScript Interview

Here are 11 questions to provide a deeper understanding of the fundamentals of JavaScript.

Q1. Can JavaScript codes be hidden from older browsers that don’t have support for JavaScript?

Ans. The browsers that support JavaScript will understand the JavaScript codes and execute the statements written between the tags. Browsers without the support for JavaScript, although might recognize the tags. For hiding the JavaScript codes from old browsers: Add “” without the quotes in the code before the

Q2. What function does namespacing perform in JavaScript?

Ans. To group the desired functions, variables, etc. with a unique name, namespacing is used. This helps in improving overall modularity in the coding and makes it reusable.

Q3. Are there any relations between JavaScript and ECMAScript?

Ans. ECMAScript acts as rules and guidelines for JavaScript, which is a scripting language mainly used in web development by developers.

Q4. Does this statement declare anything?

Var myArray = [ [ [ ] ] ] ;

Ans. Javascript does not provide a three-dimensional array natively. This code declares a three-dimensional array.

Q5. Explain what are decodeURI() and encodeURI()?

Ans. The encodeURI() is used to encode a URI. It converts a URL into a hex coding. Whereas, a DecodeURI() turns back the URL to normal.

Q6. Explain the use of unescape() and escape() functions?

Ans. The escape() function is used for transferring the information from one computer to another through a network by coding a string. The unescape() function performs a crucial function for decoding the coded string.

Q7. What is the unshift() method?

Ans. To add as many elements as you want above an array, you can use the unshift() method. This method is functional from the very start of the array unlike the push ().

Q8. What do you mean by Screen objects?

Ans. The screen object in JavaScript holds information about the browser screen, meaning it provides

The height of the browser screen, also the total height including the taskbar
The width of the browser screen, also the total width including the taskbar
The bit depth of images on the browser screen

Q9. State the various functional components in JavaScript?

Ans. There are two different functional components in JavaScript: -

First-class Functions: Functions are used as first-class objects. It means that functions can be executed as arguments to other functions, can be called back as values from other functions, and can be assigned to variables or stored in data structures.
Nested Functions: While invoking the main function, ‘everytime’ nested functions are called. They are functions, which are defined within other functions and thus called Nested functions.

Q10. What is the role of deferred scripts in JavaScript?

Ans. The defer attribute is used only for external scripts, and only usable when the src attribute is present. Deferred scripts are used to reduce the load time of webpages. This is done by delaying the execution of the script till the HTML parser is running, which removes the delay in loading the webpage which occurs due to the execution of a heavy script or slow speed of the server.

Q11. Explain the use of event handlers in JavaScript?

Ans. When a user clicks on a link, thus making an activity, events occur as a result. An event handler organizes all the events that take place thereafter. Event Handler is attributive to objects. This attribute includes the event’s name and the action taken after an event occurs

The beauty of scripting software lies in its potential. Explore the depths of JavaScript by understanding how the core principles work and the tricks to overcome issues that you might encounter while programming.

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