HTML - Class or ID Attribute
The class and id attributes are nearly identical. They play no direct role in formatting your elements but rather serve behind the scenes for scripting and Cascading Style Sheets (CSS). The role of classification and identifying elements will become more apparent as your learn CSS.
The idea is that you can classify or id certain a tag and later format the tag using Cascading Style Sheets. It becomes necessary when you have two or more of the same element on a page (like a
tag) but want them to be different in appearance.
<p id="italicsparagraph">Paragraph type 1 Italics</p>
<p id="boldparagraph">Paragraph type 2 Bold</p>
Paragraph type 1 Italics
Paragraph type 2 Bold