The id and class Selectors
In addition to setting a style for a HTML element, CSS allows you to specify
your own selectors called "id" and "class".
The id Selector
The id selector is used to specify a style for a single, unique element.
The id selector uses the id attribute of the HTML element, and is defined
with a "#".
The style rule below will be applied to the element with id="para1":
Example
#para1
{
text-align:center;
color:red;
}
The class Selector
The class selector is used to specify a style for a group of elements. Unlike the id
selector, the class selector is most often used on several elements.
This allows you to set a particular style for many HTML elements with the same class.
The class selector uses the HTML class
attribute, and is defined with a "."
In the example
below, all HTML elements with class="center" will be center-aligned:
Example
.center {text-align:center;}
You can also specify that only specific HTML elements should be affected by a
class.
In the example
below, all p elements with class="center" will be center-aligned:
Example
p.center {text-align:center;}