What is the difference between id and class in CSS, and when should I use them? [duplicate]

Answer 1

You can assign a class to many elements. You can also assign more than one class to an element, eg.

in Bootstrap. You can assign the id only to one. So if you want to make many elements look the same, eg. list items, you choose class. If you want to trigger certain actions on an element using JavaScript you will probably use id.