What is the difference between var

How can you clone an object? 17., const and let? 18. What is a class in JavaScript? 19. How does a class differ from a JS object? 20. Is JavaScript a type language? 21. How to determine whether the object is frozen? 22.? 23. What does the eval() method do? 24. What is NaN? How to check that a variable is NaN? 25. What is destructuring? 26. How to check if a substring exists in a string? 27.? 28. What are the setTimeout and setInterval methods for? 29. What are link types? 30. In what cases are anonymous functions use? 31. What does promise return? 32. is the difference between promise and callback.

What is a temporary dead zone

What is the difference between attributes and properties? 34. What are cookies in JavaScript? 35. What is the difference between localStorage, cookies and sessionStorage? 36. What is the difference between parameters and arguments? 37. What is Malta Phone Number List Object Destructuring? 38. What are modules? 39. What is a Set object? 40. What are the default parameters (Default Parameters)? 41. What is an object wrapper (Wrapper Objects)? 42. What does the trycatch construct do? 43. What is XSS? 44. Why is WeakSet use? 45. What is the difference between Set and WeakSet.

How to check if a number is finite

​​What methods are available in WeakSet? 47. Why is WeakMap use? 48. What is the difference between Map and WeakMap? 49. What methods are available in WeakMap? 50. What is recursion? 51. Why is the seal() method use? 52. What is the main difference AERO Leads between Object.keys(), Object.values() and Object.entries() methods? 53. What is an event target or target element (event.target)? 54. What is the current target of the event (event.current Target)? Data 55. What are the data types in JS? 56. What do null and undefine have in common? 57. What is the difference between undefine and is not define.