JavaScript interview question 1. What is the difference of undefined and not defined in JavaScript? 2. What is negative infinity? 3. Explain JavaScript Data Types? 4. What is use of isNaN function? 5. What is a closure in JavaScript? Provide an example? 6. How do you check an object is an array or not? 7. What is 'this' keyword in JavaScript? 8. What is data type of variables of in JavaScript? 9. Which keywords are used to handle exceptions? 10. Types of errors in JavaScript? 11. How are JavaScript and ECMA Script related What is significance, and what are the benefits, of including 'use strict' at the beginning of a JavaScript source file? 12. How to write HTML code dynamically using JavaScript? 13. How can you read properties of Object in JS? 14. What is hoisting and what's a benefit? 15. What is arrow function? How many ways you can declare give an example? 16. What is callback? Explain with example? 17. What is callback hell? 18. What is first error callback? 19. What is a prompt box? 20. 17. What is the instanceof operator in JavaScript? 21. How to create a DOM element? Set innher HTML or use createElement? 22. What is DOM give example?
23. Is there any difference between window and document? 24. What is event bubble? How does event flows in DOM? 25. How to generate onclick event on a button to add new paragraph?
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