The element selector selects HTML elements based on the element name.
The id selector uses the id attribute of an HTML element to select a specific element. The id of an element is unique within a page, so the id selector is used to select one unique element! To select an element with a specific id, write a hash (#) character, followed by the id of the element.
Note: An id name cannot start with a number!
The class selector selects HTML elements with a specific class attribute. To select elements with a specific class, write a period (.) character, followed by the class name.
Note: A class name cannot start with a number!
The universal selector (*) selects all HTML elements on the page.