CSS selectors
In CSS, selectors are used to target the HTML elements on our web pages that we want to style. There are a wide variety of CSS selectors available, allowing for fine-grained precision when selecting elements to style. In this article and its sub-articles we’ll run through the different types in great detail, seeing how they work.
| Prerequisites: | Basic computer literacy, basic software installed, basic knowledge of working with files, HTML basics (study Introduction to HTML), and an idea of how CSS works (study CSS first steps.) |
|---|---|
| Objective: | To learn how CSS selectors work in detail. |
What is a selector?
A CSS selector is the first part of a CSS Rule. It is a pattern of elements and other terms that tell the browser which HTML elements should be selected to have the CSS property values inside the rule applied to them. The element or elements which are selected by the selector are referred to as the subject of the selector.
In other articles you may have met some different selectors, and learned that there are selectors that target the document in different ways — for example by selecting an element such as h1 , or a class such as .special .
In CSS, selectors are defined in the CSS Selectors specification; like any other part of CSS they need to have support in browsers for them to work. The majority of selectors that you will come across are defined in the Level 3 Selectors specification and Level 4 Selectors specification, which are both mature specifications, therefore you will find excellent browser support for these selectors.
Selector lists
If you have more than one thing which uses the same CSS then the individual selectors can be combined into a selector list so that the rule is applied to all of the individual selectors. For example, if I have the same CSS for an h1 and also a class of .special , I could write this as two separate rules.
h1 color: blue; > .special color: blue; > I could also combine these into a selector list, by adding a comma between them.
White space is valid before or after the comma. You may also find the selectors more readable if each is on a new line.
In the live example below try combining the two selectors which have identical declarations. The visual display should be the same after combining them.
When you group selectors in this way, if any selector is syntactically invalid, the whole rule will be ignored.
In the following example, the invalid class selector rule will be ignored, whereas the h1 would still be styled.
h1 color: blue; > ..special color: blue; > When combined however, neither the h1 nor the class will be styled as the entire rule is deemed invalid.
Types of selectors
There are a few different groupings of selectors, and knowing which type of selector you might need will help you to find the right tool for the job. In this article’s subarticles we will look at the different groups of selectors in more detail.
Type, class, and ID selectors
This group includes selectors that target an HTML element such as an .
It also includes selectors which target a class:
Class selectors
The CSS class selector matches elements based on the contents of their class attribute.
Syntax
.class_name style properties > Note that this is equivalent to the following attribute selector :
[class~=class_name] style properties > Examples
CSS
.red color: #f33; > .yellow-bg background: #ffa; > .fancy font-weight: bold; text-shadow: 4px 4px 3px #77f; > HTML
p class="red">This paragraph has red text.p> p class="red yellow-bg"> This paragraph has red text and a yellow background. p> p class="red fancy">This paragraph has red text and "fancy" styling.p> p>This is just a regular paragraph.p>
Result
Specifications
Browser compatibility
BCD tables only load in the browser
See also
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This page was last modified on Jul 22, 2023 by MDN contributors.
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