diegocard / js-questions

:question: Compilation of JavaScript and jQuery interview questions and answers

JavaScript and jQuery Q&A

###Index

Theorical

1. What is JavaScript?
2. What is the difference between JavaScript and Jscript?
3. Which are JavaScripts's primitive datatypes?
4. Does JavaScript Support automatic type conversion?
5. What are global variables? How are they declared? What are the problems with using globals?
6. What is the difference between undefined and null?
7. What is JavaScript's this keyword?
8. What is event bubbling?
9. How do JavaScript timers work? What is a drawback of JavaScript timers?
10. What are JavaScript closures?

Web

1. What is the difference between window.onload and onDocumentReady?
2. What is unobtrusive JavaScript? How to add behavior to an element using JavaScript?

Syntax

1. What is the difference between “==” and “===”?
2. How do you get a Checkbox's status? (whether it is checked or not)
3. What does isNaN function do?
4. How do you change the style/class on any element using only JavaScript?

Object Oriented Programming

1. Does JavaScript support OOP?
2. Inheritance
3. Constructors
4. Encapsulation
5. Abstraction
6. Polymorphism

jQuery

1. How do I select elements when I already have a DOM element?
2. How do I test whether an element has a particular class?
3. How do I test whether an element exists?
4. How do I determine the state of a toggled element?
5. How do I select an element by an ID that has characters used in CSS notation?
6. How do I disable/enable a form element?
7. How do I check/uncheck a checkbox input or radio button?
8. How do I get the text value of a selected option?
9. How do I replace text from the 3rd element of a list of 10 items?
10. How do I pull a native DOM element from a jQuery object?
11. How do I create a jQuery plugin?

Sources

• http://www.codeproject.com/Articles/620811/Latest-JavaScript-Interview-Questions-and-Answers
• http://www.techrepublic.com/blog/software-engineer/javascript-interview-questions-and-answers/
• https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Details_of_the_Object_Model
• http://vikasrao.wordpress.com/2010/02/07/common-javascript-interview-questions/
• http://learn.jquery.com/using-jquery-core/faq/