You can define your own selectors with the class selector class and the identity selector ID.
The advantage of doing this is that depending on the class or ID, you can perform the same HTML element differently.
In CSS, the class selector is preceded by a half-width English period (.), and the ID is preceded by a half-point English well number (#).
Looks like this:
#top {background-color: #ccc; padding:1em}. intro {color:red; font-weight:bold;}
HTML and CSS are connected with the attribute ID and class. Like this:
<div id= "Top" >
The difference between ID and class is that the ID is used on a unique element, and class is used on more than one element.
You can also apply a selector to a specified HTML element and place the HTML selector in front of it, so P.jam {whatever} will be applied to paragraphs with class "jam".
An ID name is usually uniquely defined within a page, so defining CSS in a page usually suggests using class, so you can reuse your CSS. and leave the ID to the JavaScript that needs the most HTML element.
