After reading this, you will understand the differences between class and ID selector in CSS styles.

You can use the class selector and the identifier selector ID to define your own selector.

The benefit of doing so is that depending on the class or ID, you can behave the same HTML element differently.

In CSS, the class selector is prior to a half-width English period (.), and the ID is prior to the half-width English well number.

It looks like this:

# Top {background-color: # CCC; padding: 1em}. Intro {color: red; font-weight: bold ;}
The link between HTML and CSS uses the property ID and class. Like this:

<Div id = "TOP">

The difference between ID and class is that ID is used on unique elements, while class is used on more than one element.

You can also apply a selection character to a specified HTML element and place the HTML selection character in front of it. Therefore, P. jam {whatever} will be applied to the section with the class "Jam.

An ID name is usually uniquely defined in a page. Therefore, we recommend that you use class to define CSS in the page so that you can reuse your CSS. and leave the ID to the Javascript that requires the most HTML elements.