Selectors

Selectors are used to style HTML elements according to their type and/or attributes.

All markups can be selected with the * selector:

* {
  /* declarations here */
}

Selecting by Type

The element selector selects HTML elements based on the element name.

Syntax

element-name {
  /* declarations here */
}

The element-type must be a valid HTML element.

Example

In the following example, all of the <p> elements on the page will be centered with a red text color:

p {
  text-align: center;
  color: red;
}

Selecting by Attribute

The class selector selects elements that are assigned a class attribute, it can be used across multiple elements, and begins with a period, .. Similarly, the id selector selects an HTML element that has an id attribute. In contrast, the id selector can only be applied once and begins with the hashtag symbol, #.

Syntax

#id-name {
  /* declarations here */
}

.class-name {
  /* declarations here */
}

element[attribute='value'] {
  /* declarations here */
}

The id of an element is unique within a page, so the id selector is used to select one unique element. An element can be selected with a specific id, by using a hash (#) character, followed by id-name.

Multiple class values can be assigned to a single element. Elements are selected by class with a period (.) character, followed by class-name. Unlike id values, class values can be duplicated on a page with different elements.

Example

The following rules select elements based on id, class, and other attributes:

#para1 {
  text-align: center;
  color: red;
}

.center {
  text-align: center;
  color: red;
}

li[title='red'] {
  background-color: red;
  color: #fff;
}

It can also be specified that only certain HTML elements with a given class should be styled. For example, here, only <p> tags with a class of "center" will have its text center-aligned:

p.center {
  text-align: center;
  color: red;
}

The CSS Grouping Selector

The grouping selector selects a group of HTML elements and applies a specific set of styles to each one of them, helping in minimizing the codebase.

Syntax

elm1, elm2, elm3 {
  /* Declarations are inserted here */
}

In the following example, a particular set of styles is applied to all the h1, h2, and p elements:

Example

h1,
h2,
p {
  text-align: center;
  color: red;
}

Video Walkthrough

Watch this video on how to compare the various selectors in CSS.