the id attribute what is it ??

Answer 1

Unique identity for the class.

Answer 2

Thank you

Answer 3

ID used for to provide a unique identity to any element. It can be used to provide unique style using CSS or can be used in javascript or any other script you use for functionality to access that particular element.
Class is completely different than ID. Usually Class is used to apply same styling or access number of elements together. It is kind of imposing that those are the elements you would like to put in some sort of same group.

Answer 4

brother Andreas class is reuseable. it can be used again but id can't be used again and again